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Sample records for evades macrophage defenses

  1. Amphibian macrophage development and antiviral defenses.

    PubMed

    Grayfer, Leon; Robert, Jacques

    2016-05-01

    Macrophage lineage cells represent the cornerstone of vertebrate physiology and immune defenses. In turn, comparative studies using non-mammalian animal models have revealed that evolutionarily distinct species have adopted diverse molecular and physiological strategies for controlling macrophage development and functions. Notably, amphibian species present a rich array of physiological and environmental adaptations, not to mention the peculiarity of metamorphosis from larval to adult stages of development, involving drastic transformation and differentiation of multiple new tissues. Thus it is not surprising that different amphibian species and their respective tadpole and adult stages have adopted unique hematopoietic strategies. Accordingly and in order to establish a more comprehensive view of these processes, here we review the hematopoietic and monopoietic strategies observed across amphibians, describe the present understanding of the molecular mechanisms driving amphibian, an in particular Xenopus laevis macrophage development and functional polarization, and discuss the roles of macrophage-lineage cells during ranavirus infections. PMID:26705159

  2. Macrophage defense mechanisms against intracellular bacteria

    PubMed Central

    Weiss, Günter; Schaible, Ulrich E

    2015-01-01

    Macrophages and neutrophils play a decisive role in host responses to intracellular bacteria including the agent of tuberculosis (TB), Mycobacterium tuberculosis as they represent the forefront of innate immune defense against bacterial invaders. At the same time, these phagocytes are also primary targets of intracellular bacteria to be abused as host cells. Their efficacy to contain and eliminate intracellular M. tuberculosis decides whether a patient initially becomes infected or not. However, when the infection becomes chronic or even latent (as in the case of TB) despite development of specific immune activation, phagocytes have also important effector functions. Macrophages have evolved a myriad of defense strategies to combat infection with intracellular bacteria such as M. tuberculosis. These include induction of toxic anti-microbial effectors such as nitric oxide and reactive oxygen intermediates, the stimulation of microbe intoxication mechanisms via acidification or metal accumulation in the phagolysosome, the restriction of the microbe's access to essential nutrients such as iron, fatty acids, or amino acids, the production of anti-microbial peptides and cytokines, along with induction of autophagy and efferocytosis to eliminate the pathogen. On the other hand, M. tuberculosis, as a prime example of a well-adapted facultative intracellular bacterium, has learned during evolution to counter-balance the host's immune defense strategies to secure survival or multiplication within this otherwise hostile environment. This review provides an overview of innate immune defense of macrophages directed against intracellular bacteria with a focus on M. tuberculosis. Gaining more insights and knowledge into this complex network of host-pathogen interaction will identify novel target sites of intervention to successfully clear infection at a time of rapidly emerging multi-resistance of M. tuberculosis against conventional antibiotics. PMID:25703560

  3. Polyglycerol-coated nanodiamond as a macrophage-evading platform for selective drug delivery in cancer cells.

    PubMed

    Zhao, Li; Xu, Yong-Hong; Akasaka, Tsukasa; Abe, Shigeaki; Komatsu, Naoki; Watari, Fumio; Chen, Xiao

    2014-07-01

    A successful targeted drug delivery device for cancer chemotherapy should ideally be able to avoid non-specific uptake by nonmalignant cells, particularly the scavenging monocyte-macrophage system as well as targeting efficacy to bring the drug preferentially into tumor cells. To this purpose, we developed a platform based on detonation nanodiamond (dND) with hyperbranched polyglycerol (PG) coating (dND-PG). dND-PG was first demonstrated to evade non-specific cell uptake, particularly by macrophages (U937). RGD targeting peptide was then conjugated to dND-PG through multistep organic transformations to yield dND-PG-RGD that still evaded macrophage uptake but was preferentially taken up by targeted A549 cancer cells (expressing RGD peptide receptors). dND-PG and dND-PG-RGD showed good aqueous solubility and cytocompatibitlity. Subsequently, the anticancer agent doxorubicin (DOX) was loaded through acid-labile hydrazone linkage to yield dND-PG-DOX and dND-PG-RGD-DOX. Their cellular uptake and cytotoxicity were compared against DOX in A549 cells and U937 macrophages. It was found that dND-PG-DOX uptake was substantially reduced, displaying little toxicity in either type of cells by virtue of PG coating, whereas dND-PG-RGD-DOX exerted selective toxicity to A549 cells over U937 macrophages that are otherwise highly sensitive to DOX. Finally, dND-PG was demonstrated to have little influence on U937 macrophage cell functions, except for a slight increase of TNF-α production in resting U937 macrophages. dND-PG is a promising drug carrier for realization of highly selective drug delivery in tumor cells through specific uptake mechanisms, with minimum uptake in and influence on macrophages. PMID:24720879

  4. Apoptosis is an innate defense function of macrophages against Mycobacterium tuberculosis

    PubMed Central

    Behar, SM; Martin, CJ; Booty, MG; Nishimura, T; Zhao, X; Gan, H; Divangahi, M; Remold, HG

    2011-01-01

    Two different forms of death are commonly observed when Mycobacterium tuberculosis (Mtb)-infected macrophages die: (i) necrosis, a death modality defined by cell lysis and (ii) apoptosis, a form of death that maintains an intact plasma membrane. Necrosis is a mechanism used by bacteria to exit the macrophage, evade host defenses, and spread. In contrast, apoptosis of infected macrophages is associated with diminished pathogen viability. Apoptosis occurs when tumor necrosis factor activates the extrinsic death domain pathway, leading to caspase-8 activation. In addition, mitochondrial outer membrane permeabilization leading to activation of the intrinsic apoptotic pathway is required. Both pathways lead to caspase-3 activation, which results in apoptosis. We have recently demonstrated that during mycobacterial infection, cell death is regulated by the eicosanoids, prostaglandin E2 (proapoptotic) and lipoxin (LX)A4 (pronecrotic). Although PGE2 protects against necrosis, virulent Mtb induces LXA4 and inhibits PGE2 production. Under such conditions, mitochondrial inner membrane damage leads to macrophage necrosis. Thus, virulent Mtb subverts eicosanoid regulation of cell death to foil innate defense mechanisms of the macrophage. PMID:21307848

  5. Biofilm-derived Legionella pneumophila evades the innate immune response in macrophages

    PubMed Central

    Abu Khweek, Arwa; Fernández Dávila, Natalia S.; Caution, Kyle; Akhter, Anwari; Abdulrahman, Basant A.; Tazi, Mia; Hassan, Hoda; Novotny, Laura A.; Bakaletz, Lauren O.; Amer, Amal O.

    2013-01-01

    Legionella pneumophila, the causative agent of Legionnaire's disease, replicates in human alveolar macrophages to establish infection. There is no human-to-human transmission and the main source of infection is L. pneumophila biofilms established in air conditioners, water fountains, and hospital equipments. The biofilm structure provides protection to the organism from disinfectants and antibacterial agents. L. pneumophila infection in humans is characterized by a subtle initial immune response, giving time for the organism to establish infection before the patient succumbs to pneumonia. Planktonic L. pneumophila elicits a strong immune response in murine, but not in human macrophages enabling control of the infection. Interactions between planktonic L. pneumophila and murine or human macrophages have been studied for years, yet the interface between biofilm-derived L. pneumophila and macrophages has not been explored. Here, we demonstrate that biofilm-derived L. pneumophila replicates significantly more in murine macrophages than planktonic bacteria. In contrast to planktonic L. pneumophila, biofilm-derived L. pneumophila lacks flagellin expression, do not activate caspase-1 or -7 and trigger less cell death. In addition, while planktonic L. pneumophila is promptly delivered to lysosomes for degradation, most biofilm-derived bacteria were enclosed in a vacuole that did not fuse with lysosomes in murine macrophages. This study advances our understanding of the innate immune response to biofilm-derived L. pneumophila and closely reproduces the natural mode of infection in human. PMID:23750338

  6. Biofilm-derived Legionella pneumophila evades the innate immune response in macrophages.

    PubMed

    Abu Khweek, Arwa; Fernández Dávila, Natalia S; Caution, Kyle; Akhter, Anwari; Abdulrahman, Basant A; Tazi, Mia; Hassan, Hoda; Novotny, Laura A; Bakaletz, Lauren O; Amer, Amal O

    2013-01-01

    Legionella pneumophila, the causative agent of Legionnaire's disease, replicates in human alveolar macrophages to establish infection. There is no human-to-human transmission and the main source of infection is L. pneumophila biofilms established in air conditioners, water fountains, and hospital equipments. The biofilm structure provides protection to the organism from disinfectants and antibacterial agents. L. pneumophila infection in humans is characterized by a subtle initial immune response, giving time for the organism to establish infection before the patient succumbs to pneumonia. Planktonic L. pneumophila elicits a strong immune response in murine, but not in human macrophages enabling control of the infection. Interactions between planktonic L. pneumophila and murine or human macrophages have been studied for years, yet the interface between biofilm-derived L. pneumophila and macrophages has not been explored. Here, we demonstrate that biofilm-derived L. pneumophila replicates significantly more in murine macrophages than planktonic bacteria. In contrast to planktonic L. pneumophila, biofilm-derived L. pneumophila lacks flagellin expression, do not activate caspase-1 or -7 and trigger less cell death. In addition, while planktonic L. pneumophila is promptly delivered to lysosomes for degradation, most biofilm-derived bacteria were enclosed in a vacuole that did not fuse with lysosomes in murine macrophages. This study advances our understanding of the innate immune response to biofilm-derived L. pneumophila and closely reproduces the natural mode of infection in human. PMID:23750338

  7. Antioxidant Defenses of Francisella tularensis Modulate Macrophage Function and Production of Proinflammatory Cytokines.

    PubMed

    Rabadi, Seham M; Sanchez, Belkys C; Varanat, Mrudula; Ma, Zhuo; Catlett, Sally V; Melendez, Juan Andres; Malik, Meenakshi; Bakshi, Chandra Shekhar

    2016-03-01

    Francisella tularensis, the causative agent of a fatal human disease known as tularemia, has been used in the bioweapon programs of several countries in the past, and now it is considered a potential bioterror agent. Extreme infectivity and virulence of F. tularensis is due to its ability to evade immune detection and to suppress the host's innate immune responses. However, Francisella-encoded factors and mechanisms responsible for causing immune suppression are not completely understood. Macrophages and neutrophils generate reactive oxygen species (ROS)/reactive nitrogen species as a defense mechanism for the clearance of phagocytosed microorganisms. ROS serve a dual role; at high concentrations they act as microbicidal effector molecules that destroy intracellular pathogens, and at low concentrations they serve as secondary signaling messengers that regulate the expression of various inflammatory mediators. We hypothesized that the antioxidant defenses of F. tularensis maintain redox homeostasis in infected macrophages to prevent activation of redox-sensitive signaling components that ultimately result in suppression of pro-inflammatory cytokine production and macrophage microbicidal activity. We demonstrate that antioxidant enzymes of F. tularensis prevent the activation of redox-sensitive MAPK signaling components, NF-κB signaling, and the production of pro-inflammatory cytokines by inhibiting the accumulation of ROS in infected macrophages. We also report that F. tularensis inhibits ROS-dependent autophagy to promote its intramacrophage survival. Collectively, this study reveals novel pathogenic mechanisms adopted by F. tularensis to modulate macrophage innate immune functions to create an environment permissive for its intracellular survival and growth. PMID:26644475

  8. A Stenotrophomonas maltophilia Strain Evades a Major Caenorhabditis elegans Defense Pathway.

    PubMed

    White, Corin V; Darby, Brian J; Breeden, Robert J; Herman, Michael A

    2016-02-01

    Stenotrophomonas maltophilia is a ubiquitous bacterium and an emerging nosocomial pathogen. This bacterium is resistant to many antibiotics, associated with a number of infections, and a significant health risk, especially for immunocompromised patients. Given that Caenorhabditis elegans shares many conserved genetic pathways and pathway components with higher organisms, the study of its interaction with bacterial pathogens has biomedical implications. S. maltophilia has been isolated in association with nematodes from grassland soils, and it is likely that C. elegans encounters this bacterium in nature. We found that a local S. maltophilia isolate, JCMS, is more virulent than the other S. maltophilia isolates (R551-3 and K279a) tested. JCMS virulence correlates with intestinal distension and bacterial accumulation and requires the bacteria to be alive. Many of the conserved innate immune pathways that serve to protect C. elegans from various pathogenic bacteria also play a role in combating S. maltophilia JCMS. However, S. maltophilia JCMS is virulent to normally pathogen-resistant DAF-2/16 insulin-like signaling pathway mutants. Furthermore, several insulin-like signaling effector genes were not significantly differentially expressed between S. maltophilia JCMS and avirulent bacteria (Escherichia coli OP50). Taken together, these findings suggest that S. maltophilia JCMS evades the pathogen resistance conferred by the loss of DAF-2/16 pathway components. In summary, we have discovered a novel host-pathogen interaction between C. elegans and S. maltophilia and established a new animal model with which to study the mode of action of this emerging nosocomial pathogen. PMID:26644380

  9. A Stenotrophomonas maltophilia Strain Evades a Major Caenorhabditis elegans Defense Pathway

    PubMed Central

    White, Corin V.; Darby, Brian J.; Breeden, Robert J.

    2015-01-01

    Stenotrophomonas maltophilia is a ubiquitous bacterium and an emerging nosocomial pathogen. This bacterium is resistant to many antibiotics, associated with a number of infections, and a significant health risk, especially for immunocompromised patients. Given that Caenorhabditis elegans shares many conserved genetic pathways and pathway components with higher organisms, the study of its interaction with bacterial pathogens has biomedical implications. S. maltophilia has been isolated in association with nematodes from grassland soils, and it is likely that C. elegans encounters this bacterium in nature. We found that a local S. maltophilia isolate, JCMS, is more virulent than the other S. maltophilia isolates (R551-3 and K279a) tested. JCMS virulence correlates with intestinal distension and bacterial accumulation and requires the bacteria to be alive. Many of the conserved innate immune pathways that serve to protect C. elegans from various pathogenic bacteria also play a role in combating S. maltophilia JCMS. However, S. maltophilia JCMS is virulent to normally pathogen-resistant DAF-2/16 insulin-like signaling pathway mutants. Furthermore, several insulin-like signaling effector genes were not significantly differentially expressed between S. maltophilia JCMS and avirulent bacteria (Escherichia coli OP50). Taken together, these findings suggest that S. maltophilia JCMS evades the pathogen resistance conferred by the loss of DAF-2/16 pathway components. In summary, we have discovered a novel host-pathogen interaction between C. elegans and S. maltophilia and established a new animal model with which to study the mode of action of this emerging nosocomial pathogen. PMID:26644380

  10. Bordetella pertussis modulates human macrophage defense gene expression.

    PubMed

    Valdez, Hugo Alberto; Oviedo, Juan Marcos; Gorgojo, Juan Pablo; Lamberti, Yanina; Rodriguez, Maria Eugenia

    2016-08-01

    Bordetella pertussis, the etiological agent of whooping cough, still causes outbreaks. We recently found evidence that B. pertussis can survive and even replicate inside human macrophages, indicating that this host cell might serve as a niche for persistence. In this work, we examined the interaction of B. pertussis with a human monocyte cell line (THP-1) that differentiates into macrophages in culture in order to investigate the host cell response to the infection and the mechanisms that promote that intracellular survival. To that end, we investigated the expression profile of a selected number of genes involved in cellular bactericidal activity and the inflammatory response during the early and late phases of infection. The bactericidal and inflammatory response of infected macrophages was progressively downregulated, while the number of THP-1 cells heavily loaded with live bacteria increased over time postinfection. Two of the main toxins of B. pertussis, pertussis toxin (Ptx) and adenylate cyclase (CyaA), were found to be involved in manipulating the host cell response. Therefore, failure to express either toxin proved detrimental to the development of intracellular infections by those bacteria. Taken together, these results support the relevance of host defense gene manipulation to the outcome of the interaction between B. pertussis and macrophages. PMID:27465637

  11. Streptococcus uberis strains isolated from the bovine mammary gland evade immune recognition by mammary epithelial cells, but not of macrophages.

    PubMed

    Günther, Juliane; Czabanska, Anna; Bauer, Isabel; Leigh, James A; Holst, Otto; Seyfert, Hans-Martin

    2016-01-01

    Streptococcus uberis is frequently isolated from the mammary gland of dairy cattle. Infection with some strains can induce mild subclinical inflammation whilst others induce severe inflammation and clinical mastitis. We compared here the inflammatory response of primary cultures of bovine mammary epithelial cells (pbMEC) towards S. uberis strains collected from clinical or subclinical cases (seven strains each) of mastitis with the strong response elicited by Escherichia coli. Neither heat inactivated nor live S. uberis induced the expression of 10 key immune genes (including TNF, IL1B, IL6). The widely used virulent strain 0140J and the avirulent strain, EF20 elicited similar responses; as did mutants defective in capsule (hasA) or biofilm formation (sub0538 and sub0539). Streptococcus uberis failed to activate NF-κB in pbMEC or TLR2 in HEK293 cells, indicating that S. uberis particles did not induce any TLR-signaling in MEC. However, preparations of lipoteichoic acid (LTA) from two strains strongly induced immune gene expression and activated NF-κB in pbMEC, without the involvement of TLR2. The immune-stimulatory LTA must be arranged in the intact S. uberis such that it is unrecognizable by the relevant pathogen receptors of the MEC. The absence of immune recognition is specific for MEC, since the same S. uberis preparations strongly induced immune gene expression and NF-κB activity in the murine macrophage model cell RAW264.7. Hence, the sluggish immune response of MEC and not of professional immune cells to this pathogen may aid establishment of the often encountered belated and subclinical phenotype of S. uberis mastitis. PMID:26738804

  12. Macrophages and tissue injury: agents of defense or destruction?

    PubMed

    Laskin, Debra L; Sunil, Vasanthi R; Gardner, Carol R; Laskin, Jeffrey D

    2011-01-01

    The past several years have seen the accumulation of evidence demonstrating that tissue injury induced by diverse toxicants is due not only to their direct effects on target tissues but also indirectly to the actions of resident and infiltrating macrophages. These cells release an array of mediators with cytotoxic, pro- and anti-inflammatory, angiogenic, fibrogenic, and mitogenic activity, which function to fight infections, limit tissue injury, and promote wound healing. However, following exposure to toxicants, macrophages can become hyperresponsive, resulting in uncontrolled or dysregulated release of mediators that exacerbate acute tissue injury and/or promote the development of chronic diseases such as fibrosis and cancer. Evidence suggests that the diverse activity of macrophages is mediated by distinct subpopulations that develop in response to signals within their microenvironment. Understanding the precise roles of these different macrophage populations in the pathogenic response to toxicants is key to designing effective treatments for minimizing tissue damage and chronic disease and for facilitating wound repair. PMID:20887196

  13. Mechanisms of Defense against Intracellular Pathogens Mediated by Human Macrophages.

    PubMed

    Bloom, Barry R; Modlin, Robert L

    2016-06-01

    The key question our work has sought to address has been, "What are the necessary and sufficient conditions that engender protection from intracellular pathogens in the human host?" The origins of this work derive from a long-standing interest in the mechanisms of protection against two such paradigmatic intracellular pathogens, Mycobacterium tuberculosis and Mycobacterium leprae, that have brilliantly adapted to the human host. It was obvious that these pathogens, which cause chronic diseases and persist in macrophages, must have acquired subtle strategies to resist host microbicidal mechanisms, yet since the vast majority of individuals infected with M. tuberculosis do not develop disease, there must be some potent human antimicrobial mechanisms. What follows is not a comprehensive review of the vast literature on the role of human macrophages in protection against infectious disease, but a summary of the research in our two laboratories with collaborators that we hope has contributed to some understanding of mechanisms of resistance and pathogenesis. While mouse models revealed some necessary conditions for protection, e.g., innate immunity, Th1 cells and their cytokines, and major histocompatibility complex class I-restricted T cells, here we emphasize multiple antimicrobial mechanisms that exist in human macrophages that differ from those of most experimental animals. Prominent here is the vitamin D-dependent antimicrobial pathway common to human macrophages activated by innate and acquired immune responses, mediated by antimicrobial peptides, e.g., cathelicidin, through an interleukin-15- and interleukin-32-dependent common pathway that is necessary for macrophage killing of M. tuberculosis in vitro. PMID:27337485

  14. Plasma gelsolin improves lung host defense against pneumonia by enhancing macrophage NOS3 function

    PubMed Central

    Yang, Zhiping; Chiou, Terry Ting-Yu; Stossel, Thomas P.

    2015-01-01

    Plasma gelsolin (pGSN) functions as part of the “extracellular actin-scavenging system,” but its potential to improve host defense against infection has not been studied. In a mouse model of primary pneumococcal pneumonia, recombinant human pGSN (rhu-pGSN) caused enhanced bacterial clearance, reduced acute inflammation, and improved survival. In vitro, rhu-pGSN rapidly improved lung macrophage uptake and killing of bacteria (Streptococcus pneumoniae, Escherichia coli, and Francisella tularensis). pGSN triggers activating phosphorylation (Ser1177) of macrophage nitric oxide synthase type III (NOS3), an enzyme with important bactericidal functions in lung macrophages. rhu-pGSN failed to enhance bacterial killing by NOS3−/− macrophages in vitro or bacterial clearance in NOS3−/− mice in vivo. Prophylaxis with immunomodulators may be especially relevant for patients at risk for secondary bacterial pneumonia, e.g., after influenza. Treatment of mice with pGSN challenged with pneumococci on postinfluenza day 7 (the peak of enhanced susceptibility to secondary infection) caused a ∼15-fold improvement in bacterial clearance, reduced acute neutrophilic inflammation, and markedly improved survival, even without antibiotic therapy. pGSN is a potential immunomodulator for improving lung host defense against primary and secondary bacterial pneumonia. PMID:25957291

  15. Plasma gelsolin improves lung host defense against pneumonia by enhancing macrophage NOS3 function.

    PubMed

    Yang, Zhiping; Chiou, Terry Ting-Yu; Stossel, Thomas P; Kobzik, Lester

    2015-07-01

    Plasma gelsolin (pGSN) functions as part of the "extracellular actin-scavenging system," but its potential to improve host defense against infection has not been studied. In a mouse model of primary pneumococcal pneumonia, recombinant human pGSN (rhu-pGSN) caused enhanced bacterial clearance, reduced acute inflammation, and improved survival. In vitro, rhu-pGSN rapidly improved lung macrophage uptake and killing of bacteria (Streptococcus pneumoniae, Escherichia coli, and Francisella tularensis). pGSN triggers activating phosphorylation (Ser(1177)) of macrophage nitric oxide synthase type III (NOS3), an enzyme with important bactericidal functions in lung macrophages. rhu-pGSN failed to enhance bacterial killing by NOS3(-/-) macrophages in vitro or bacterial clearance in NOS3(-/-) mice in vivo. Prophylaxis with immunomodulators may be especially relevant for patients at risk for secondary bacterial pneumonia, e.g., after influenza. Treatment of mice with pGSN challenged with pneumococci on postinfluenza day 7 (the peak of enhanced susceptibility to secondary infection) caused a ∼15-fold improvement in bacterial clearance, reduced acute neutrophilic inflammation, and markedly improved survival, even without antibiotic therapy. pGSN is a potential immunomodulator for improving lung host defense against primary and secondary bacterial pneumonia. PMID:25957291

  16. Neisseria gonorrhoeae Modulates Iron-Limiting Innate Immune Defenses in Macrophages

    PubMed Central

    Zughaier, Susu M.; Kandler, Justin L.; Shafer, William M.

    2014-01-01

    Neisseria gonorrhoeae is a strict human pathogen that causes the sexually transmitted infection termed gonorrhea. The gonococcus can survive extracellularly and intracellularly, but in both environments the bacteria must acquire iron from host proteins for survival. However, upon infection the host uses a defensive response by limiting the bioavailability of iron by a number of mechanisms including the enhanced expression of hepcidin, the master iron-regulating hormone, which reduces iron uptake from the gut and retains iron in macrophages. The host also secretes the antibacterial protein NGAL, which sequesters bacterial siderophores and therefore inhibits bacterial growth. To learn whether intracellular gonococci can subvert this defensive response, we examined expression of host genes that encode proteins involved in modulating levels of intracellular iron. We found that N. gonorrhoeae can survive in association (tightly adherent and intracellular) with monocytes and macrophages and upregulates a panel of its iron-responsive genes in this environment. We also found that gonococcal infection of human monocytes or murine macrophages resulted in the upregulation of hepcidin, NGAL, and NRAMP1 as well as downregulation of the expression of the gene encoding the short chain 3-hydroxybutyrate dehydrogenase (BDH2); BDH2 catalyzes the production of the mammalian siderophore 2,5-DHBA involved in chelating and detoxifying iron. Based on these findings, we propose that N. gonorrhoeae can subvert the iron-limiting innate immune defenses to facilitate iron acquisition and intracellular survival. PMID:24489950

  17. Human Macrophage SCN5A Activates an Innate Immune Signaling Pathway for Antiviral Host Defense*

    PubMed Central

    Jones, Alexis; Kainz, Danielle; Khan, Faatima; Lee, Cara; Carrithers, Michael D.

    2014-01-01

    Pattern recognition receptors contain a binding domain for pathogen-associated molecular patterns coupled to a signaling domain that regulates transcription of host immune response genes. Here, a novel mechanism that links pathogen recognition to channel activation and downstream signaling is proposed. We demonstrate that an intracellular sodium channel variant, human macrophage SCN5A, initiates signaling and transcription through a calcium-dependent isoform of adenylate cyclase, ADCY8, and the transcription factor, ATF2. Pharmacological stimulation with a channel agonist or treatment with cytoplasmic poly(I:C), a mimic of viral dsRNA, activates this pathway to regulate expression of SP100-related genes and interferon β. Electrophysiological analysis reveals that the SCN5A variant mediates nonselective outward currents and a small, but detectable, inward current. Intracellular poly(I:C) markedly augments an inward voltage-sensitive sodium current and inhibits the outward nonselective current. These results suggest human macrophage SCN5A initiates signaling in an innate immune pathway relevant to antiviral host defense. It is postulated that SCN5A is a novel pathogen sensor and that this pathway represents a channel activation-dependent mechanism of transcriptional regulation. PMID:25368329

  18. Cytosolic Phospholipase A2α and Eicosanoids Regulate Expression of Genes in Macrophages Involved in Host Defense and Inflammation

    PubMed Central

    Suram, Saritha; Silveira, Lori J.; Mahaffey, Spencer; Brown, Gordon D.; Bonventre, Joseph V.; Williams, David L.; Gow, Neil A. R.; Bratton, Donna L.; Murphy, Robert C.; Leslie, Christina C.

    2013-01-01

    The role of Group IVA cytosolic phospholipase A2 (cPLA2α) activation in regulating macrophage transcriptional responses to Candida albicans infection was investigated. cPLA2α releases arachidonic acid for the production of eicosanoids. In mouse resident peritoneal macrophages, prostacyclin, prostaglandin E2 and leukotriene C4 were produced within minutes of C. albicans addition before cyclooxygenase 2 expression. The production of TNFα was lower in C. albicans-stimulated cPLA2α+/+ than cPLA2α-/- macrophages due to an autocrine effect of prostaglandins that increased cAMP to a greater extent in cPLA2α+/+ than cPLA2α-/- macrophages. For global insight, differential gene expression in C. albicans-stimulated cPLA2α+/+ and cPLA2α-/- macrophages (3 h) was compared by microarray. cPLA2α+/+ macrophages expressed 86 genes at lower levels and 181 genes at higher levels than cPLA2α-/- macrophages (≥2-fold, p<0.05). Several pro-inflammatory genes were expressed at lower levels (Tnfα, Cx3cl1, Cd40, Ccl5, Csf1, Edn1, CxCr7, Irf1, Irf4, Akna, Ifnγ, several IFNγ-inducible GTPases). Genes that dampen inflammation (Socs3, Il10, Crem, Stat3, Thbd, Thbs1, Abca1) and genes involved in host defense (Gja1, Csf3, Trem1, Hdc) were expressed at higher levels in cPLA2α+/+ macrophages. Representative genes expressed lower in cPLA2α+/+ macrophages (Tnfα, Csf1) were increased by treatment with a prostacyclin receptor antagonist and protein kinase A inhibitor, whereas genes expressed at higher levels (Crem, Nr4a2, Il10, Csf3) were suppressed. The results suggest that C. albicans stimulates an autocrine loop in macrophages involving cPLA2α, cyclooxygenase 1-derived prostaglandins and increased cAMP that globally effects expression of genes involved in host defense and inflammation. PMID:23950842

  19. Phosphoethanolamine Modification of Neisseria gonorrhoeae Lipid A Reduces Autophagy Flux in Macrophages.

    PubMed

    Zughaier, Susu M; Kandler, Justin L; Balthazar, Jacqueline T; Shafer, William M

    2015-01-01

    Autophagy, an ancient homeostasis mechanism for macromolecule degradation, performs an important role in host defense by facilitating pathogen elimination. To counteract this host defense strategy, bacterial pathogens have evolved a variety of mechanisms to avoid or otherwise dysregulate autophagy by phagocytic cells so as to enhance their survival during infection. Neisseria gonorrhoeae is a strictly human pathogen that causes the sexually transmitted infection, gonorrhea. Phosphoethanolamine (PEA) addition to the 4' position of the lipid A (PEA-lipid A) moiety of the lipooligosaccharide (LOS) produced by gonococci performs a critical role in this pathogen's ability to evade innate defenses by conferring decreased susceptibility to cationic antimicrobial (or host-defense) peptides, complement-mediated killing by human serum and intraleukocytic killing by human neutrophils compared to strains lacking this PEA decoration. Heretofore, however, it was not known if gonococci can evade autophagy and if so, whether PEA-lipid A contributes to this ability. Accordingly, by using murine macrophages and human macrophage-like phagocytic cell lines we investigated if PEA decoration of gonococcal lipid A modulates autophagy formation. We report that infection with PEA-lipid A-producing gonococci significantly reduced autophagy flux in murine and human macrophages and enhanced gonococcal survival during their association with macrophages compared to a PEA-deficient lipid A mutant. Our results provide further evidence that PEA-lipid A produced by gonococci is a critical component in the ability of this human pathogen to evade host defenses. PMID:26641098

  20. Phosphoethanolamine Modification of Neisseria gonorrhoeae Lipid A Reduces Autophagy Flux in Macrophages

    PubMed Central

    Zughaier, Susu M.; Kandler, Justin L.; Balthazar, Jacqueline T.; Shafer, William M.

    2015-01-01

    Autophagy, an ancient homeostasis mechanism for macromolecule degradation, performs an important role in host defense by facilitating pathogen elimination. To counteract this host defense strategy, bacterial pathogens have evolved a variety of mechanisms to avoid or otherwise dysregulate autophagy by phagocytic cells so as to enhance their survival during infection. Neisseria gonorrhoeae is a strictly human pathogen that causes the sexually transmitted infection, gonorrhea. Phosphoethanolamine (PEA) addition to the 4' position of the lipid A (PEA-lipid A) moiety of the lipooligosaccharide (LOS) produced by gonococci performs a critical role in this pathogen’s ability to evade innate defenses by conferring decreased susceptibility to cationic antimicrobial (or host-defense) peptides, complement-mediated killing by human serum and intraleukocytic killing by human neutrophils compared to strains lacking this PEA decoration. Heretofore, however, it was not known if gonococci can evade autophagy and if so, whether PEA-lipid A contributes to this ability. Accordingly, by using murine macrophages and human macrophage-like phagocytic cell lines we investigated if PEA decoration of gonococcal lipid A modulates autophagy formation. We report that infection with PEA-lipid A-producing gonococci significantly reduced autophagy flux in murine and human macrophages and enhanced gonococcal survival during their association with macrophages compared to a PEA-deficient lipid A mutant. Our results provide further evidence that PEA-lipid A produced by gonococci is a critical component in the ability of this human pathogen to evade host defenses. PMID:26641098

  1. Macrophages from Patients with Cirrhotic Ascites Showed Function Alteration of Host Defense Receptor

    PubMed Central

    Ahmed, Abdel Motaal M.; Kadaru, Abdel Gadir Y.; Omer, Ibtihal; Musa, Ahmed M.; Enan, Khalid; El Khidir, Isam M.; Williams, Roger

    2014-01-01

    Background Patients with cirrhotic ascites (PCA) are susceptible to spontaneous bacterial peritonitis (SBP) which has increased morbidity and mortality. Since some host defense aspects of peritoneal macrophages (PMф) from PCA are altered this study examined factors related to receptor-mediated phagocytosis. Methods Twelve PCA were studied. PMɸ were isolated from ascitic fluid (AF) samples removed from these patients. Uptake of mannose receptor (MR)-specific ligand, fluorescein isothiocyanate-mannosylated-bovine serum albumin (FITC-man-BSA), by patients' PMɸ and controls, a human monocytic cell line, was measured pre- and post-IL-4 treatment. Phagocytosis of FITC-labeled yeast particles by patients' PMɸ was measured pre- and post-IL-4 treatment. Fluorescence values were obtained using a spectrofuorometer. MRC1 gene was analyzed in blood samples from PCA and controls, healthy donors, using standard polymerase chain reaction (PCR) technique. Results Past SBP episode(s) were reported in 58.3% of patients. Mean AF volume analyzed per patient was 1.3L. PMɸ ratio in cell yield was 53.73% (SD 18.1). Mean uptake absorbance of patients' PMф was 0.0841 (SD 0.077) compared to 0.338 (SD 0.34) of controls, P = 0.023. Following IL-4 treatment absorbance increased to 0.297 (SD 0.28) in patients' PMф (P = 0.018 on paired sample t-test), and to 0.532 (SD 0.398 in controls (P = 0.053 on independent sample t-test). Mean phagocytosis absorbance of patients' PMф was 0.1250 (SD 0.032) before IL-4 treatment compared to 0.2300 (SD 0.104) after (P = 0.026). PCR analysis for MRC1 gene was negative in all PCA samples compared to positive results in all controls. Conclusion Since decreased phagocytosis and MR uptake were enhanced post-IL-4 treatment MR downregulation pre-treatment is plausible. Negative PCR results for MRC1 might suggest an anomaly, but this awaits further ellucidation. These altered host defense findings are relevant to infection pathophysiology, and their

  2. Macrophage Migration Inhibitory Factor Contributes to Host Defense against Acute Trypanosoma cruzi Infection

    PubMed Central

    Reyes, José L.; Terrazas, Luis I.; Espinoza, Bertha; Cruz-Robles, David; Soto, Virgilia; Rivera-Montoya, Irma; Gómez-García, Lorena; Snider, Heidi; Satoskar, Abhay R.; Rodríguez-Sosa, Miriam

    2006-01-01

    Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is involved in the host defense against several pathogens. Here we used MIF−/− mice to determine the role of endogenous MIF in the regulation of the host immune response against Trypanosoma cruzi infection. MIF−/− mice displayed high levels of blood and tissue parasitemia, developed severe heart and skeletal muscle immunopathology, and succumbed to T. cruzi infection faster than MIF+/+ mice. The enhanced susceptibility of MIF−/− mice to T. cruzi was associated with reduced levels of proinflammatory cytokines, such as tumor necrosis factor alpha, interleukin-12 (IL-12), IL-18, gamma interferon (IFN-γ), and IL-1β, in their sera and reduced production of IL-12, IFN-γ, and IL-4 by spleen cells during the early phase of infection. At all time points, antigen-stimulated splenocytes from MIF+/+ and MIF−/− mice produced comparable levels of IL-10. MIF−/− mice also produced significantly less Th1-associated antigen-specific immunoglobulin G2a (IgG2a) throughout the infection, but both groups produced comparable levels of Th2-associated IgG1. Lastly, inflamed hearts from T. cruzi-infected MIF−/− mice expressed increased transcripts for IFN-γ, but fewer for IL-12 p35, IL-12 p40, IL-23, and inducible nitric oxide synthase, compared to MIF+/+ mice. Taken together, our findings show that MIF plays a role in controlling acute T. cruzi infection. PMID:16714544

  3. Cutaneous Na+ storage strengthens the antimicrobial barrier function of the skin and boosts macrophage-driven host defense.

    PubMed

    Jantsch, Jonathan; Schatz, Valentin; Friedrich, Diana; Schröder, Agnes; Kopp, Christoph; Siegert, Isabel; Maronna, Andreas; Wendelborn, David; Linz, Peter; Binger, Katrina J; Gebhardt, Matthias; Heinig, Matthias; Neubert, Patrick; Fischer, Fabian; Teufel, Stefan; David, Jean-Pierre; Neufert, Clemens; Cavallaro, Alexander; Rakova, Natalia; Küper, Christoph; Beck, Franz-Xaver; Neuhofer, Wolfgang; Muller, Dominik N; Schuler, Gerold; Uder, Michael; Bogdan, Christian; Luft, Friedrich C; Titze, Jens

    2015-03-01

    Immune cells regulate a hypertonic microenvironment in the skin; however, the biological advantage of increased skin Na(+) concentrations is unknown. We found that Na(+) accumulated at the site of bacterial skin infections in humans and in mice. We used the protozoan parasite Leishmania major as a model of skin-prone macrophage infection to test the hypothesis that skin-Na(+) storage facilitates antimicrobial host defense. Activation of macrophages in the presence of high NaCl concentrations modified epigenetic markers and enhanced p38 mitogen-activated protein kinase (p38/MAPK)-dependent nuclear factor of activated T cells 5 (NFAT5) activation. This high-salt response resulted in elevated type-2 nitric oxide synthase (Nos2)-dependent NO production and improved Leishmania major control. Finally, we found that increasing Na(+) content in the skin by a high-salt diet boosted activation of macrophages in a Nfat5-dependent manner and promoted cutaneous antimicrobial defense. We suggest that the hypertonic microenvironment could serve as a barrier to infection. PMID:25738463

  4. Cutaneous Na+ storage strengthens the antimicrobial barrier function of the skin and boosts macrophage-driven host defense

    PubMed Central

    Jantsch, Jonathan; Schatz, Valentin; Friedrich, Diana; Schröder, Agnes; Kopp, Christoph; Siegert, Isabel; Maronna, Andreas; Wendelborn, David; Linz, Peter; Binger, Katrina J.; Gebhardt, Matthias; Heinig, Matthias; Neubert, Patrick; Fischer, Fabian; Teufel, Stefan; David, Jean-Pierre; Neufert, Clemens; Cavallaro, Alexander; Rakova, Natalia; Küper, Christoph; Beck, Franz-Xaver; Neuhofer, Wolfgang; Muller, Dominik N.; Schuler, Gerold; Uder, Michael; Bogdan, Christian; Luft, Friedrich C.; Titze, Jens

    2015-01-01

    Summary Immune cells regulate a hypertonic microenvironment in the skin; however, the biological advantage of increased skin Na+ concentrations is unknown. We found that Na+ accumulated at the site of bacterial skin infections in humans and in mice. We used the protozoan parasite Leishmania major as a model of skin-prone macrophage infection to test the hypothesis that skin-Na+ storage facilitates antimicrobial host defense. Activation of macrophages in the presence of high NaCl concentrations modified epigenetic markers and enhanced p38 mitogen-activated protein kinase (p38/MAPK)-dependent nuclear factor of activated T cells 5 (NFAT5) activation. This high-salt response resulted in elevated type-2 nitric oxide synthase (Nos2)-dependent NO production and improved Leishmania major control. Finally, we found that increasing Na+ content in the skin by a high-salt diet boosted activation of macrophages in an Nfat5-dependent manner and promoted cutaneous antimicrobial defense. We suggest that the hypertonic microenvironment could serve as a barrier to infection. PMID:25738463

  5. Virulent but not Avirulent Mycobacterium tuberculosis Can Evade the Growth Inhibitory Action of a T Helper 1–dependent, Nitric Oxide Synthase 2–independent Defense in Mice

    PubMed Central

    Jung, Yu-Jin; LaCourse, Ronald; Ryan, Lynn; North, Robert J.

    2002-01-01

    Control of infection with virulent Mycobacterium tuberculosis (Mtb) in mice is dependent on the generation of T helper (Th)1-mediated immunity that serves, via secretion of interferon (IFN)-γ and other cytokines, to upregulate the antimycobacterial function of macrophages of which the synthesis of inducible nitric oxide synthase (NOS)2 is an essential event. As a means to understanding the basis of Mtb virulence, the ability of gene-deleted mice incapable of making NOS2 (NOS2−/−), gp91Phox subunit of the respiratory burst NADPH-oxidase complex (Phox−/−), or either enzyme (NOS2/Phox−/−), to control airborne infection with the avirulent R1Rv and H37Ra strains of Mtb was compared with their ability control infection with the virulent H37Rv strain. NOS2−/−, Phox−/−, and NOS2/Phox−/− mice showed no deficiency in ability to control infection with either strain of avirulent Mtb. By contrast, NOS2−/− mice, but not Phox−/− mice, were incapable of controlling H37Rv infection and died early from neutrophil-dominated lung pathology. Control of infection with avirulent, as well as virulent Mtb, depended on the synthesis of IFN-γ, and was associated with a substantial increase in the synthesis in the lungs of mRNA for IFN-γ and NOS2, and with production of NOS2 by macrophages at sites of infection. The results indicate that virulent, but not avirulent, Mtb can overcome the growth inhibitory action of a Th1–dependent, NOS2-independent mechanism of defense. PMID:12370260

  6. Colonize, evade, flourish

    PubMed Central

    Rubin, Erica J; Trent, M Stephen

    2013-01-01

    Helicobacter pylori is an adapted gastric pathogen that colonizes the human stomach, causing severe gastritis and gastric cancer. A hallmark of infection is the ability of this organism to evade detection by the human immune system. H. pylori has evolved a number of features to achieve this, many of which involve glyco-conjugates including the lipopolysaccharide, peptidoglycan layer, glycoproteins, and glucosylated cholesterol. These major bacterial components possess unique features from those of other gram-negative organisms, including differences in structure, assembly, and modification. These defining characteristics of H. pylori glycobiology help the pathogen establish a long-lived infection by providing camouflage, modulating the host immune response, and promoting virulence mechanisms. In this way, glyco-conjugates are essential for H. pylori pathogenicity and survival, allowing it to carve out a niche in the formidable environment of the human stomach. PMID:23859890

  7. Interdiction of a Markovian evader

    SciTech Connect

    Hagberg, Aric; Izraelevitz, David; Pan, Feng; Gutfraind, Alexander

    2008-01-01

    Network interdiction is a combinatorial optimization problem on an activity network arising in a number of important security-related applications. It is classically formulated as a bilevel maximin problem representing an 'interdictor' and an 'evader'. The evader tries to move from a source node to the target node along the shortest or safest path while the interdictor attempts to frustrate this motion by cutting edges or nodes. The interdiction objective is to find the optimal set of edges to cut given that there is a finite interdiction budget and the interdictor must move first. We reformulate the interdiction problem for stochastic evaders by introducing a model in which the evader follows a Markovian random walk guided by the least-cost path to the target. This model can represent incomplete knowledge about the evader and the graph as well as partial interdiction. We formulate the optimization problem for this model and show how, by exploiting topological ordering of the nodes, one can achieve an order-of-magnitude speedup in computing the objective function. We also introduce an evader-motion-based heuristic that can significantly improve solution quality by providing a global view of the network to approximation methods.

  8. Mitochondrial respiratory-chain adaptations in macrophages contribute to antibacterial host defense.

    PubMed

    Garaude, Johan; Acín-Pérez, Rebeca; Martínez-Cano, Sarai; Enamorado, Michel; Ugolini, Matteo; Nistal-Villán, Estanislao; Hervás-Stubbs, Sandra; Pelegrín, Pablo; Sander, Leif E; Enríquez, José A; Sancho, David

    2016-09-01

    Macrophages tightly scale their core metabolism after being activated, but the precise regulation of the mitochondrial electron-transport chain (ETC) and its functional implications are currently unknown. Here we found that recognition of live bacteria by macrophages transiently decreased assembly of the ETC complex I (CI) and CI-containing super-complexes and switched the relative contributions of CI and CII to mitochondrial respiration. This was mediated by phagosomal NADPH oxidase and the reactive oxygen species (ROS)-dependent tyrosine kinase Fgr. It required Toll-like receptor signaling and the NLRP3 inflammasome, which were both connected to bacterial viability-specific immune responses. Inhibition of CII during infection with Escherichia coli normalized serum concentrations of interleukin 1β (IL-1β) and IL-10 to those in mice treated with dead bacteria and impaired control of bacteria. We have thus identified ETC adaptations as an early immunological-metabolic checkpoint that adjusts innate immune responses to bacterial infection. PMID:27348412

  9. Bacillus cereus immune escape: a journey within macrophages.

    PubMed

    Tran, Seav-Ly; Ramarao, Nalini

    2013-10-01

    During bacterial infection, professional phagocytes are attracted to the site of infection, where they constitute a first line of host cell defense. Their function is to engulf and destroy the pathogens. Thus, bacteria must withstand the bactericidal activity of professional phagocytes, including macrophages to counteract the host immune system. Bacillus cereus infections are characterized by bacteremia despite the accumulation of inflammatory cells at the site of infection. This implies that the bacteria have developed means of resisting the host immune system. Bacillus cereus spores survive, germinate, and multiply in contact with macrophages, eventually producing toxins that kill these cells. However, the exact mechanism by which B. cereus evades immune attack remains unclear. This review addresses the interaction between B. cereus and macrophages, highlighting, in particular, the ways in which the bacteria escape the microbicidal activities of professional phagocytes. PMID:23827020

  10. Role of Granulocyte Macrophage Colony-Stimulating Factor in Host Defense Against Pulmonary Cryptococcus neoformans Infection during Murine Allergic Bronchopulmonary Mycosis

    PubMed Central

    Chen, Gwo-Hsiao; Olszewski, Michal A.; McDonald, Roderick A.; Wells, Jason C.; Paine, Robert; Huffnagle, Gary B.; Toews, Galen B.

    2007-01-01

    We investigated the role of granulocyte macrophage colony-stimulating factor (GM-CSF) in host defense in a murine model of pulmonary cryptococcosis induced by intratracheal inoculation of Cryptococcus neoformans. Pulmonary C. neoformans infection of C57BL/6 mice is an established model of an allergic bronchopulmonary mycosis. Our objective was to determine whether GM-CSF regulates the pulmonary Th2 immune response in C. neoformans-infected C57BL/6 mice. Long-term pulmonary fungistasis was lost in GM-CSF knockout (GM−/−) mice, resulting in increased pulmonary burden of fungi between weeks 3 and 5. GM-CSF was required for the early influx of macrophages and CD4 and CD8 T cells into the lungs but was not required later in the infection. Lack of GM-CSF also resulted in reduced eosinophil recruitment and delayed recruitment of mononuclear cells into the airspace. Macrophages from GM+/+ mice showed numerous hallmarks of alternatively activated macrophages: higher numbers of intracellular cryptococci, YM1 crystals, and induction of CCL17. These hallmarks are absent in macrophages from GM−/− mice. Mucus-producing goblet cells were abundantly present within the bronchial epithelial layer in GM+/+ mice but not in GM−/− mice at week 5 after infection. Production of both Th1 and Th2 cytokines was impaired in the absence of GM-CSF, consistent with both reduced C. neoformans clearance and absence of allergic lung pathology. PMID:17322386

  11. Evader Interdiction and Collateral Damage

    SciTech Connect

    Gutfraind, Alexander

    2011-01-01

    In network interdiction problems, evaders (hostile agents or data packets) are moving through a network towards their targets and we wish to choose sensor placement locations in order to intercept them before they reach their destinations. Sensor locations should be chosen economically, balancing security gains with cost, including the inconvenience sensors inflict upon innocent travelers. We give optimal sensor allocation algorithms for several classes of special graphs and hardness and optimal approximation results for general graphs, including for deterministic or Markov chain-based and oblivious or reactive evaders. In a similar-sounding but much different problem setting posed by [10] where the innocent travelers can also be reactive, we again give optimal algorithms for special cases and hardness and (essentially) optimal approximation results on general graphs.

  12. Leishmania amazonensis Amastigotes Highly Express a Tryparedoxin Peroxidase Isoform That Increases Parasite Resistance to Macrophage Antimicrobial Defenses and Fosters Parasite Virulence

    PubMed Central

    Henard, Calvin A.; Carlsen, Eric D.; Hay, Christie; Kima, Peter E.; Soong, Lynn

    2014-01-01

    Professional phagocytes generate a myriad of antimicrobial molecules to kill invading microorganisms, of which nitrogen oxides are integral in controlling the obligate intracellular pathogen Leishmania. Although reactive nitrogen species produced by the inducible nitric oxide synthase (iNOS) can promote the clearance of intracellular parasites, some Leishmania species/stages are relatively resistant to iNOS-mediated antimicrobial activity. The underlying mechanism for this resistance remains largely uncharacterized. Here, we show that the amastigote form of L. amazonensis is hyper-resistant to the antimicrobial actions of cytokine-activated murine and human macrophages as compared to its promastigote counterpart. Amastigotes exhibit a marked ability to directly counter the cytotoxicity of peroxynitrite (ONOO−), a leishmanicidal oxidant that is generated during infection through the combined enzymatic activities of NADPH oxidase and iNOS. The enhanced antinitrosative defense of amastigotes correlates with the increased expression of a tryparedoxin peroxidase (TXNPx) isoform that is also upregulated in response to iNOS enzymatic activity within infected macrophages. Accordingly, ectopic over-expression of the TXNPx isoform by L. amazonensis promastigotes significantly enhances parasite resistance against ONOO− cytotoxicity. Moreover, TXNPx-overexpressing parasites exhibit greater intra-macrophage survival, and increased parasite growth and lesion development in a murine model of leishmaniasis. Our investigations indicate that TXNPx isoforms contribute to Leishmania's ability to adapt to and antagonize the hostile microenvironment of cytokine-activated macrophages, and provide a mechanistic explanation for persistent infection in experimental and human leishmaniasis. PMID:25033301

  13. Arginase II Restricts Host Defense to Helicobacter pylori by Attenuating Inducible Nitric Oxide Synthase Translation in Macrophages

    PubMed Central

    Lewis, Nuruddeen D.; Asim, Mohammad; Barry, Daniel P.; Singh, Kshipra; de Sablet, Thibaut; Boucher, Jean-Luc; Gobert, Alain P.; Chaturvedi, Rupesh; Wilson, Keith T.

    2010-01-01

    Helicobacter pylori infection of the stomach causes peptic ulcer disease and gastric cancer. Despite eliciting a vigorous immune response, the bacterium persists for the life of the host. An important antimicrobial mechanism is the production of NO derived from inducible NO synthase (iNOS). We have reported that macrophages can kill H. pylori in vitro by an NO-dependent mechanism, but supraphysiologic levels of the iNOS substrate L-arginine are required. Because H. pylori induces arginase activity in macrophages, we determined if this restricts NO generation by reducing L-arginine availability. Inhibition of arginase with S-(2-boronoethyl)-L-cysteine (BEC) significantly enhanced NO generation in H. pylori-stimulated RAW 264.7 macrophages by enhancing iNOS protein translation but not iNOS mRNA levels. This effect resulted in increased killing of H. pylori that was attenuated with an NO scavenger. In contrast, inhibition of arginase in macrophages activated by the colitis-inducing bacterium Citrobacter rodentium increased NO without affecting iNOS levels. H. pylori upregulated levels of arginase II (Arg2) mRNA and protein, which localized to mitochondria, whereas arginase I was not induced. Increased iNOS protein and NO levels were also demonstrated by small interfering RNA knockdown of Arg2 and in peritoneal macrophages from C57BL/6 Arg2−/− mice. In H. pylori-infected mice, treatment with BEC or deletion of Arg2 increased iNOS protein levels and NO generation in gastric macrophages, but treatment of Arg2−/− mice with BEC had no additional effect. These studies implicate Arg2 in the immune evasion of H. pylori by causing intracellular depletion of L-arginine and thus reduction of NO-dependent bactericidal activity. PMID:20097867

  14. Surface Zn-proteinase as a molecule for defense of Leishmania mexicana amazonensis promastigotes against cytolysis inside macrophage phagolysosomes.

    PubMed Central

    Seay, M B; Heard, P L; Chaudhuri, G

    1996-01-01

    The role of the surface membrane Zn-proteinase in protecting the cellular integrity of the macrophage parasite Leishmania mexicana amazonensis from intraphagolysosomal cytolysis was studied. These cells lose their infectivity to host macrophages after prolonged cultivation in axenic growth medium. The virulent and attenuated variants of the parasite cells were cloned. Failure of these attenuated parasite cells to survive inside macrophage phagolysosomes is associated with 20- to 50-fold reduction in the expression of surface gp63 protein. In situ inhibition of gp63 proteinase activity inside Leishmania-infected macrophage phagolysosomes with targeted delivery of an inhibitor of gp63 proteinase activity, 1,10-phenanthroline, selectively eliminated intracellular Leishmania amastigotes, further suggesting the importance of this proteinase in phagolysosomal survival of the parasite. An upstream sequence (US) of the gp63 gene was cloned in front of the bacterial chloramphenicol acetyltransferase (CAT) gene in plasmid pCATbasic. Transfection of L. mexicana amazonensis cells with this recombinant plasmid showed that expression of the CAT gene from this US is 15- to 20-fold higher in virulent clones than in avirulent clones of the parasite. Band shift analysis with the cloned US also showed that binding of protein(s) was 15- to 20-fold higher in virulent cell extract than in avirulent cell extract. Coating of attenuated cells or liposomes with proteolytically active gp63 protects them from degradation inside macrophage phagolysosomes. These results suggest a novel mechanism of survival of this phagolysosomal parasite with the help of its surface Zn-proteinase. PMID:8945556

  15. Evader Interdiction: Algorithms, Complexity and Collateral Damage

    PubMed Central

    Johnson, Matthew P.; Gutfraind, Alexander; Ahmadizadeh, Kiyan

    2013-01-01

    In network interdiction problems, evaders (e.g., hostile agents or data packets) are moving through a network toward targets and we wish to choose locations for sensors in order to intercept the evaders. The evaders might follow deterministic routes or Markov chains, or they may be reactive, i.e., able to change their routes in order to avoid the sensors. The challenge in such problems is to choose sensor locations economically, balancing interdiction gains with costs, including the inconvenience sensors inflict upon innocent travelers. We study the objectives of (1) maximizing the number of evaders captured when limited by a budget on sensing cost and, (2) capturing all evaders as cheaply as possible. We give algorithms for optimal sensor placement in several classes of special graphs and hardness and approximation results for general graphs, including evaders who are deterministic, Markov chain-based, reactive and unreactive. A similar-sounding but fundamentally different problem setting was posed by Glazer and Rubinstein where both evaders and innocent travelers are reactive. We again give optimal algorithms for special cases and hardness and approximation results on general graphs. PMID:25332514

  16. Optimal interdiction of unreactive Markovian evaders

    SciTech Connect

    Hagberg, Aric; Pan, Feng; Gutfraind, Alex

    2009-01-01

    The interdiction problem arises in a variety of areas including military logistics, infectious disease control, and counter-terrorism. In the typical formulation of network interdiction. the task of the interdictor is to find a set of edges in a weighted network such that the removal of those edges would increase the cost to an evader of traveling on a path through the network. Our work is motivated by cases in which the evader has incomplete information about the network or lacks planning time or computational power, e.g. when authorities set up roadblocks to catch bank robbers, the criminals do not know all the roadblock locations or the best path to use for their escape. We introduce a model of network interdiction in which the motion of one or more evaders is described by Markov processes on a network and the evaders are assumed not to react to interdiction decisions. The interdiction objective is to find a node or set. of size at most B, that maximizes the probability of capturing the evaders. We prove that similar to the classical formulation this interdiction problem is NP-hard. But unlike the classical problem our interdiction problem is submodular and the optimal solution can be approximated within 1-lie using a greedy algorithm. Additionally. we exploit submodularity to introduce a priority evaluation strategy that speeds up the greedy algorithm by orders of magnitude. Taken together the results bring closer the goal of finding realistic solutions to the interdiction problem on global-scale networks.

  17. A Leishmania Ortholog of Macrophage Migration Inhibitory Factor Modulates Host Macrophage Responses1

    PubMed Central

    Kamir, Daniela; Zierow, Swen; Leng, Lin; Cho, Yoonsang; Diaz, Yira; Griffith, Jason; McDonald, Courtney; Merk, Melanie; Mitchell, Robert A.; Trent, John; Chen, Yibang; Kwong, Yuen-Kwan Amy; Xiong, Huabao; Vermeire, Jon; Cappello, Michael; McMahon-Pratt, Diane; Walker, John; Bernhagen, Jurgen; Lolis, Elias; Bucala, Richard

    2009-01-01

    Parasitic organisms have evolved specialized strategies to evade immune defense mechanisms. We describe herein an ortholog of the cytokine, macrophage migration inhibitory factor (MIF), which is produced by the obligate intracellular parasite, Leishmania major. The Leishmania MIF protein, Lm1740MIF, shows significant structural homology with human MIF as revealed by a high-resolution x-ray crystal structure (1.03 Å). Differences between the two proteins in the N-terminal tautomerization site are evident, and we provide evidence for the selective, species-specific inhibition of MIF by small-molecule antagonists that target this site. Lm1740MIF shows significant binding interaction with the MIF receptor, CD74 (Kd = 2.9 × 10−8 M). Like its mammalian counterpart, Lm1740MIF induces ERK1/2 MAP kinase activation in a CD74-dependent manner and inhibits the activation-induced apoptosis of macrophages. The ability of Lm1740MIF to inhibit apoptosis may facilitate the persistence of Leishmania within the macrophage and contribute to its evasion from immune destruction. PMID:18523291

  18. A Leishmania Ortholog of Macrophage Migration Inhibitory Factor Modulates Host Macrophage Responses

    SciTech Connect

    Kamir,D.; Zierow, S.; Leng, L.; Cho, Y.; Diaz, Y.; Griffith, J.; McDonald, C.; Merk, M.; Mitchell, R.; et al

    2008-01-01

    Parasitic organisms have evolved specialized strategies to evade immune defense mechanisms. We describe herein an ortholog of the cytokine, macrophage migration inhibitory factor (MIF), which is produced by the obligate intracellular parasite, Leishmania major. The Leishmania MIF protein, Lm1740MIF, shows significant structural homology with human MIF as revealed by a high-resolution x-ray crystal structure (1.03 A). Differences between the two proteins in the N-terminal tautomerization site are evident, and we provide evidence for the selective, species-specific inhibition of MIF by small-molecule antagonists that target this site. Lm1740MIF shows significant binding interaction with the MIF receptor, CD74 (K(d) = 2.9 x 10(-8) M). Like its mammalian counterpart, Lm1740MIF induces ERK1/2 MAP kinase activation in a CD74-dependent manner and inhibits the activation-induced apoptosis of macrophages. The ability of Lm1740MIF to inhibit apoptosis may facilitate the persistence of Leishmania within the macrophage and contribute to its evasion from immune destruction.

  19. How type 1 fimbriae help Escherichia coli to evade extracellular antibiotics

    PubMed Central

    Avalos Vizcarra, Ima; Hosseini, Vahid; Kollmannsberger, Philip; Meier, Stefanie; Weber, Stefan S.; Arnoldini, Markus; Ackermann, Martin; Vogel, Viola

    2016-01-01

    To survive antibiotics, bacteria use two different strategies: counteracting antibiotic effects by expression of resistance genes or evading their effects e.g. by persisting inside host cells. Since bacterial adhesins provide access to the shielded, intracellular niche and the adhesin type 1 fimbriae increases bacterial survival chances inside macrophages, we asked if fimbriae also influenced survival by antibiotic evasion. Combined gentamicin survival assays, flow cytometry, single cell microscopy and kinetic modeling of dose response curves showed that type 1 fimbriae increased the adhesion and internalization by macrophages. This was caused by strongly decreased off-rates and affected the number of intracellular bacteria but not the macrophage viability and morphology. Fimbriae thus promote antibiotic evasion which is particularly relevant in the context of chronic infections. PMID:26728082

  20. M2 Polarization of Human Macrophages Favors Survival of the Intracellular Pathogen Chlamydia pneumoniae

    PubMed Central

    Buchacher, Tanja; Ohradanova-Repic, Anna; Stockinger, Hannes

    2015-01-01

    for the ability of C. pneumoniae to evade cellular defense and to persist in human macrophages. PMID:26606059

  1. M2 Polarization of Human Macrophages Favors Survival of the Intracellular Pathogen Chlamydia pneumoniae.

    PubMed

    Buchacher, Tanja; Ohradanova-Repic, Anna; Stockinger, Hannes; Fischer, Michael B; Weber, Viktoria

    2015-01-01

    for the ability of C. pneumoniae to evade cellular defense and to persist in human macrophages. PMID:26606059

  2. Macrophage Polarization in Inflammatory Diseases

    PubMed Central

    Liu, Yan-Cun; Zou, Xian-Biao; Chai, Yan-Fen; Yao, Yong-Ming

    2014-01-01

    Diversity and plasticity are two hallmarks of macrophages. M1 macrophages (classically activated macrophages) are pro-inflammatory and have a central role in host defense against infection, while M2 macrophages (alternatively activated macrophages) are associated with responses to anti-inflammatory reactions and tissue remodeling, and they represent two terminals of the full spectrum of macrophage activation. Transformation of different phenotypes of macrophages regulates the initiation, development, and cessation of inflammatory diseases. Here we reviewed the characters and functions of macrophage polarization in infection, atherosclerosis, obesity, tumor, asthma, and sepsis, and proposed that targeting macrophage polarization and skewing their phenotype to adapt to the microenvironment might hold great promise for the treatment of inflammatory diseases. PMID:24910531

  3. An Intracellular Arrangement of Histoplasma capsulatum Yeast-Aggregates Generates Nuclear Damage to the Cultured Murine Alveolar Macrophages.

    PubMed

    Pitangui, Nayla de Souza; Sardi, Janaina de Cássia Orlandi; Voltan, Aline R; Dos Santos, Claudia T; da Silva, Julhiany de Fátima; da Silva, Rosangela A M; Souza, Felipe O; Soares, Christiane P; Rodríguez-Arellanes, Gabriela; Taylor, Maria Lucia; Mendes-Giannini, Maria J S; Fusco-Almeida, Ana M

    2015-01-01

    Histoplasma capsulatum is responsible for a human systemic mycosis that primarily affects lung tissue. Macrophages are the major effector cells in humans that respond to the fungus, and the development of respiratory disease depends on the ability of Histoplasma yeast cells to survive and replicate within alveolar macrophages. Therefore, the interaction between macrophages and H. capsulatum is a decisive step in the yeast dissemination into host tissues. Although the role played by components of cell-mediated immunity in the host's defense system and the mechanisms used by the pathogen to evade the host immune response are well understood, knowledge regarding the effects induced by H. capsulatum in host cells at the nuclear level is limited. According to the present findings, H. capsulatum yeast cells display a unique architectural arrangement during the intracellular infection of cultured murine alveolar macrophages, characterized as a formation of aggregates that seem to surround the host cell nucleus, resembling a "crown." This extranuclear organization of yeast-aggregates generates damage on the nucleus of the host cell, producing DNA fragmentation and inducing apoptosis, even though the yeast cells are not located inside the nucleus and do not trigger changes in nuclear proteins. The current study highlights a singular intracellular arrangement of H. capsulatum yeast near to the nucleus of infected murine alveolar macrophages that may contribute to the yeast's persistence under intracellular conditions, since this fungal pathogen may display different strategies to prevent elimination by the host's phagocytic mechanisms. PMID:26793172

  4. An Intracellular Arrangement of Histoplasma capsulatum Yeast-Aggregates Generates Nuclear Damage to the Cultured Murine Alveolar Macrophages

    PubMed Central

    Pitangui, Nayla de Souza; Sardi, Janaina de Cássia Orlandi; Voltan, Aline R.; dos Santos, Claudia T.; da Silva, Julhiany de Fátima; da Silva, Rosangela A. M.; Souza, Felipe O.; Soares, Christiane P.; Rodríguez-Arellanes, Gabriela; Taylor, Maria Lucia; Mendes-Giannini, Maria J. S.; Fusco-Almeida, Ana M.

    2016-01-01

    Histoplasma capsulatum is responsible for a human systemic mycosis that primarily affects lung tissue. Macrophages are the major effector cells in humans that respond to the fungus, and the development of respiratory disease depends on the ability of Histoplasma yeast cells to survive and replicate within alveolar macrophages. Therefore, the interaction between macrophages and H. capsulatum is a decisive step in the yeast dissemination into host tissues. Although the role played by components of cell-mediated immunity in the host's defense system and the mechanisms used by the pathogen to evade the host immune response are well understood, knowledge regarding the effects induced by H. capsulatum in host cells at the nuclear level is limited. According to the present findings, H. capsulatum yeast cells display a unique architectural arrangement during the intracellular infection of cultured murine alveolar macrophages, characterized as a formation of aggregates that seem to surround the host cell nucleus, resembling a “crown.” This extranuclear organization of yeast-aggregates generates damage on the nucleus of the host cell, producing DNA fragmentation and inducing apoptosis, even though the yeast cells are not located inside the nucleus and do not trigger changes in nuclear proteins. The current study highlights a singular intracellular arrangement of H. capsulatum yeast near to the nucleus of infected murine alveolar macrophages that may contribute to the yeast's persistence under intracellular conditions, since this fungal pathogen may display different strategies to prevent elimination by the host's phagocytic mechanisms. PMID:26793172

  5. Macrophage-pathogen interactions in infectious diseases: new therapeutic insights from the zebrafish host model

    PubMed Central

    Torraca, Vincenzo; Masud, Samrah; Spaink, Herman P.; Meijer, Annemarie H.

    2014-01-01

    Studying macrophage biology in the context of a whole living organism provides unique possibilities to understand the contribution of this extremely dynamic cell subset in the reaction to infections, and has revealed the relevance of cellular and molecular processes that are fundamental to the cell-mediated innate immune response. In particular, various recently established zebrafish infectious disease models are contributing substantially to our understanding of the mechanisms by which different pathogens interact with macrophages and evade host innate immunity. Transgenic zebrafish lines with fluorescently labeled macrophages and other leukocyte populations enable non-invasive imaging at the optically transparent early life stages. Furthermore, there is a continuously expanding availability of vital reporters for subcellular compartments and for probing activation of immune defense mechanisms. These are powerful tools to visualize the activity of phagocytic cells in real time and shed light on the intriguing paradoxical roles of these cells in both limiting infection and supporting the dissemination of intracellular pathogens. This Review will discuss how several bacterial and fungal infection models in zebrafish embryos have led to new insights into the dynamic molecular and cellular mechanisms at play when pathogens encounter host macrophages. We also describe how these insights are inspiring novel therapeutic strategies for infectious disease treatment. PMID:24973749

  6. Optimal interdiction of unreactive Markovian evaders

    SciTech Connect

    Gutfraind, Alexander; Hagberg, Aric; Pan, Feng

    2008-01-01

    The network interdiction problem arises in a wide variety of areas including military logistics, infectious disease control and counter-terrorism. In the classical formulation one is given a weighted network G(N, E) and the task is to find b nodes (or edges) whose removal would maximally increase the least-cost path from a source node s to a target node r. In practical applications. G represenLs a transportation or activity network; node/edge removal is done by an agent, the 'interdictor' against another agent the 'evader' who wants to traverse G from s to t along the least-cost route. Our work is motivated by cases in which both agents have bounded rationality: e.g. when the authorities set up road blocks to catch bank robbers, neither party can plot its actions with full information about the other. We introduce a novel model of network interdiction in which the motion of (possibly) several evaders i. described by a Markov pr cess on G.We further suppose that the evaden; do not respond to interdiction decisions because of time, knowledge or computational constraint . We prove that this interdiction problem is NP-hard, like the classical formulation, but unlike the classical problem the objective function is submodular. This implies that the solution could be approximated within 1-lie using a greedy algorithm. Exploiting submodularity again. we demonstrate that a 'priority' (or 'lazy') evaluation algorithm can improve performance by orders of magnitude. Taken together, the results bring closer realistic solutions to the interdiction problem on global-scale networks.

  7. Effects of ozone on the defense to a respiratory Listeria monocytogenes infection in the rat. Suppression of macrophage function and cellular immunity and aggravation of histopathology in lung and liver during infection

    SciTech Connect

    Van Loveren, H.; Rombout, P.J.; Wagenaar, S.S.; Walvoort, H.C.; Vos, J.G.

    1988-07-01

    We have investigated the effect of exposure to ozone on defense mechanisms to a respiratory infection with Listeria monocytogenes in the rat. For this purpose rats were continuously exposed to O/sub 3/ concentrations ranging from 0.25 to 2.0 mg/m3 for a period of 1 week. In this model defense to a respiratory infection with Listeria depends on acquired specific cellular immune responses, as well as on natural nonspecific defense mechanisms. The results confirm earlier findings that show that ozone exposure can suppress the capacity of macrophages to ingest and kill Listeria. Moreover, the results show that ozone can also have a suppressive effect on the development of cellular immune responses to a respiratory Listeria infection, i.e., on T/B ratios in lung draining lymph nodes, delayed-type hypersensitivity responses to Listeria antigen, and lymphoproliferative responses in spleen and lung draining lymph nodes to Listeria antigen. The effects on the specific immune responses are especially overt if exposure to the oxidant gas occurs during an ongoing primary infection. The pathological lesions induced by a pulmonary Listeria monocytogenes infection were characterized by multifocal infiltrates of histiocytic and lymphoid cells. The foci sometimes had a granulomatous appearance. Moreover, the cellularity of the interstitial tissues was increased. In the lung many diffuse alveolar macrophages could be seen in the alveoli. Ozone exposure greatly increased the severity of the lung lesions and also of liver lesions resulting from the pulmonary infection. A prominent finding was the formation of granulomas in ozone-exposed and Listeria-infected rats.

  8. Vitamin D Is Required for IFN-γ–Mediated Antimicrobial Activity of Human Macrophages

    PubMed Central

    Fabri, Mario; Stenger, Steffen; Shin, Dong-Min; Yuk, Jae-Min; Liu, Philip T.; Realegeno, Susan; Lee, Hye-Mi; Krutzik, Stephan R.; Schenk, Mirjam; Sieling, Peter A.; Teles, Rosane; Montoya, Dennis; Iyer, Shankar S.; Bruns, Heiko; Lewinsohn, David M.; Hollis, Bruce W.; Hewison, Martin; Adams, John S.; Steinmeyer, Andreas; Zügel, Ulrich; Cheng, Genhong; Jo, Eun-Kyeong; Bloom, Barry R.; Modlin, Robert L.

    2012-01-01

    Control of tuberculosis worldwide depends on our understanding of human immune mechanisms, which combat the infection. Acquired T cell responses are critical for host defense against microbial pathogens, yet the mechanisms by which they act in humans remain unclear. We report that T cells, by the release of interferon-γ (IFN-γ), induce autophagy, phagosomal maturation, the production of antimicrobial peptides such as cathelicidin, and antimicrobial activity against Mycobacterium tuberculosis in human macrophages via a vitamin D–dependent pathway. IFN-γ induced the antimicrobial pathway in human macrophages cultured in vitamin D–sufficient sera, but not in sera from African-Americans that have lower amounts of vitamin D and who are more susceptible to tuberculosis. In vitro supplementation of vitamin D–deficient serum with 25-hydroxyvitamin D3 restored IFN-γ–induced antimicrobial peptide expression, autophagy, phagosome-lysosome fusion, and antimicrobial activity. These results suggest a mechanism in which vitamin D is required for acquired immunity to overcome the ability of intracellular pathogens to evade macrophage-mediated antimicrobial responses. The present findings underscore the importance of adequate amounts of vitamin D in all human populations for sustaining both innate and acquired immunity against infection. PMID:21998409

  9. Biology of Bony Fish Macrophages

    PubMed Central

    Hodgkinson, Jordan W.; Grayfer, Leon; Belosevic, Miodrag

    2015-01-01

    Macrophages are found across all vertebrate species, reside in virtually all animal tissues, and play critical roles in host protection and homeostasis. Various mechanisms determine and regulate the highly plastic functional phenotypes of macrophages, including antimicrobial host defenses (pro-inflammatory, M1-type), and resolution and repair functions (anti-inflammatory/regulatory, M2-type). The study of inflammatory macrophages in immune defense of teleosts has garnered much attention, and antimicrobial mechanisms of these cells have been extensively studied in various fish models. Intriguingly, both similarities and differences have been documented for the regulation of lower vertebrate macrophage antimicrobial defenses, as compared to what has been described in mammals. Advances in our understanding of the teleost macrophage M2 phenotypes likewise suggest functional conservation through similar and distinct regulatory strategies, compared to their mammalian counterparts. In this review, we discuss the current understanding of the molecular mechanisms governing teleost macrophage functional heterogeneity, including monopoetic development, classical macrophage inflammatory and antimicrobial responses as well as alternative macrophage polarization towards tissues repair and resolution of inflammation. PMID:26633534

  10. Salmonella Mitigates Oxidative Stress and Thrives in the Inflamed Gut by Evading Calprotectin-Mediated Manganese Sequestration.

    PubMed

    Diaz-Ochoa, Vladimir E; Lam, Diana; Lee, Carlin S; Klaus, Suzi; Behnsen, Judith; Liu, Janet Z; Chim, Nicholas; Nuccio, Sean-Paul; Rathi, Subodh G; Mastroianni, Jennifer R; Edwards, Robert A; Jacobo, Christina M; Cerasi, Mauro; Battistoni, Andrea; Ouellette, André J; Goulding, Celia W; Chazin, Walter J; Skaar, Eric P; Raffatellu, Manuela

    2016-06-01

    Neutrophils hinder bacterial growth by a variety of antimicrobial mechanisms, including the production of reactive oxygen species and the secretion of proteins that sequester nutrients essential to microbes. A major player in this process is calprotectin, a host protein that exerts antimicrobial activity by chelating zinc and manganese. Here we show that the intestinal pathogen Salmonella enterica serovar Typhimurium uses specialized metal transporters to evade calprotectin sequestration of manganese, allowing the bacteria to outcompete commensals and thrive in the inflamed gut. The pathogen's ability to acquire manganese in turn promotes function of SodA and KatN, enzymes that use the metal as a cofactor to detoxify reactive oxygen species. This manganese-dependent SodA activity allows the bacteria to evade neutrophil killing mediated by calprotectin and reactive oxygen species. Thus, manganese acquisition enables S. Typhimurium to overcome host antimicrobial defenses and support its competitive growth in the intestine. PMID:27281571

  11. Staphylococcus aureus Strain USA300 Perturbs Acquisition of Lysosomal Enzymes and Requires Phagosomal Acidification for Survival inside Macrophages

    PubMed Central

    Tranchemontagne, Zachary R.; Camire, Ryan B.; O'Donnell, Vanessa J.; Baugh, Jessfor

    2015-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) causes invasive, drug-resistant skin and soft tissue infections. Reports that S. aureus bacteria survive inside macrophages suggest that the intramacrophage environment may be a niche for persistent infection; however, mechanisms by which the bacteria might evade macrophage phagosomal defenses are unclear. We examined the fate of the S. aureus-containing phagosome in THP-1 macrophages by evaluating bacterial intracellular survival and phagosomal acidification and maturation and by testing the impact of phagosomal conditions on bacterial viability. Multiple strains of S. aureus survived inside macrophages, and in studies using the MRSA USA300 clone, the USA300-containing phagosome acidified rapidly and acquired the late endosome and lysosome protein LAMP1. However, fewer phagosomes containing live USA300 bacteria than those containing dead bacteria associated with the lysosomal hydrolases cathepsin D and β-glucuronidase. Inhibiting lysosomal hydrolase activity had no impact on intracellular survival of USA300 or other S. aureus strains, suggesting that S. aureus perturbs acquisition of lysosomal enzymes. We examined the impact of acidification on S. aureus intramacrophage viability and found that inhibitors of phagosomal acidification significantly impaired USA300 intracellular survival. Inhibition of macrophage phagosomal acidification resulted in a 30-fold reduction in USA300 expression of the staphylococcal virulence regulator agr but had little effect on expression of sarA, saeR, or sigB. Bacterial exposure to acidic pH in vitro increased agr expression. Together, these results suggest that S. aureus survives inside macrophages by perturbing normal phagolysosome formation and that USA300 may sense phagosomal conditions and upregulate expression of a key virulence regulator that enables its intracellular survival. PMID:26502911

  12. Macrophage polarization in pathology.

    PubMed

    Sica, Antonio; Erreni, Marco; Allavena, Paola; Porta, Chiara

    2015-11-01

    Macrophages are cells of the innate immunity constituting the mononuclear phagocyte system and endowed with remarkable different roles essential for defense mechanisms, development of tissues, and homeostasis. They derive from hematopoietic precursors and since the early steps of fetal life populate peripheral tissues, a process continuing throughout adult life. Although present essentially in every organ/tissue, macrophages are more abundant in the gastro-intestinal tract, liver, spleen, upper airways, and brain. They have phagocytic and bactericidal activity and produce inflammatory cytokines that are important to drive adaptive immune responses. Macrophage functions are settled in response to microenvironmental signals, which drive the acquisition of polarized programs, whose extremes are simplified in the M1 and M2 dichotomy. Functional skewing of monocyte/macrophage polarization occurs in physiological conditions (e.g., ontogenesis and pregnancy), as well as in pathology (allergic and chronic inflammation, tissue repair, infection, and cancer) and is now considered a key determinant of disease development and/or regression. Here, we will review evidence supporting a dynamic skewing of macrophage functions in disease, which may provide a basis for macrophage-centered therapeutic strategies. PMID:26210152

  13. Inhalation of particulate lead oxide disrupts pulmonary macrophage-mediated functions important for host defense and tumor surveillance in the lung

    SciTech Connect

    Zelikoff, J.T.; Parsons, E.; Schlesinger, R.B. )

    1993-08-01

    Lead, an immunomodulator and potential human carcinogen, is a major airborne pollutant in industrial environments which poses a serious threat to human health. Despite the wide-spread occurrence of respirable lead particles in the air, and the potential human health risks, effects associated with inhalation of particulate lead on the the lung have been poorly studied. This study was performed to determine whether inhalation of particulate lead oxide (PbO), at a concentration below the currently acceptable air lead standard for occupational exposure, disrupts macrophage (M phi) functions important for maintaining pulmonary immunocompetence. These functions include phagocytosis, production of reactive oxygen intermediates, and the biological activity of tumor necrosis factor-alpha (TNF-alpha). Rabbits exposed to PbO at 30 micrograms/m3 for 4 days (3 hr/day) were sacrificed and their lungs lavaged immediately, 24 hr, and 72 hr after the final exposure. Lactate dehydrogenase (a marker of lung cell damage) and lysozyme activity (a marker of lysosome permeability), measured in the lavage fluid, were significantly increased 24 and 72 hr after exposure. PbO produced neutrophil infiltration nor effects on M phi viability or total numbers. Effects on M phi functions were as follows. Phagocytic uptake of latex particles was reduced with increasing post-exposure time reaching a maximum inhibition at 72 hr. Inhalation of PbO enhanced hydrogen peroxide (H2O2) and superoxide anion radical (O2-) production in a time-dependent manner; effects on H2O2 began at 24 hr and were persistent up to 72 hr. Effects on TNF-alpha release/activity appeared earliest and were persistent up to 72 hr. Immediately and 24 hr after exposure, lipopolysaccharide-stimulated activity of TNF-alpha was depressed by 62 and 50%, respectively; after 72 hr, TNF-alpha release was significantly enhanced compared to control levels.

  14. Leishmania major Promastigotes Evade LC3-Associated Phagocytosis through the Action of GP63

    PubMed Central

    Matte, Christine; Casgrain, Pierre-André; Séguin, Olivier; Moradin, Neda; Hong, Wan Jin; Descoteaux, Albert

    2016-01-01

    The protozoan Leishmania parasitizes macrophages and evades the microbicidal consequences of phagocytosis through the inhibition of phagolysosome biogenesis. In this study, we investigated the impact of this parasite on LC3-associated phagocytosis, a non-canonical autophagic process that enhances phagosome maturation and functions. We show that whereas internalization of L. major promastigotes by macrophages promoted LC3 lipidation, recruitment of LC3 to phagosomes was inhibited through the action of the parasite surface metalloprotease GP63. Reactive oxygen species generated by the NOX2 NADPH oxidase are necessary for LC3-associated phagocytosis. We found that L. major promastigotes prevented, in a GP63-dependent manner, the recruitment of NOX2 to phagosomes through a mechanism that does not involve NOX2 cleavage. Moreover, we found that the SNARE protein VAMP8, which regulates phagosomal assembly of the NADPH oxidase NOX2, was down-modulated by GP63. In the absence of VAMP8, recruitment of LC3 to phagosomes containing GP63-deficient parasites was inhibited, indicating that VAMP8 is involved in the phagosomal recruitment of LC3. These findings reveal a role for VAMP8 in LC3-associated phagocytosis and highlight a novel mechanism exploited by L. major promastigotes to interfere with the host antimicrobial machinery. PMID:27280768

  15. Leishmania major Promastigotes Evade LC3-Associated Phagocytosis through the Action of GP63.

    PubMed

    Matte, Christine; Casgrain, Pierre-André; Séguin, Olivier; Moradin, Neda; Hong, Wan Jin; Descoteaux, Albert

    2016-06-01

    The protozoan Leishmania parasitizes macrophages and evades the microbicidal consequences of phagocytosis through the inhibition of phagolysosome biogenesis. In this study, we investigated the impact of this parasite on LC3-associated phagocytosis, a non-canonical autophagic process that enhances phagosome maturation and functions. We show that whereas internalization of L. major promastigotes by macrophages promoted LC3 lipidation, recruitment of LC3 to phagosomes was inhibited through the action of the parasite surface metalloprotease GP63. Reactive oxygen species generated by the NOX2 NADPH oxidase are necessary for LC3-associated phagocytosis. We found that L. major promastigotes prevented, in a GP63-dependent manner, the recruitment of NOX2 to phagosomes through a mechanism that does not involve NOX2 cleavage. Moreover, we found that the SNARE protein VAMP8, which regulates phagosomal assembly of the NADPH oxidase NOX2, was down-modulated by GP63. In the absence of VAMP8, recruitment of LC3 to phagosomes containing GP63-deficient parasites was inhibited, indicating that VAMP8 is involved in the phagosomal recruitment of LC3. These findings reveal a role for VAMP8 in LC3-associated phagocytosis and highlight a novel mechanism exploited by L. major promastigotes to interfere with the host antimicrobial machinery. PMID:27280768

  16. Respiratory Syncytial Virus Persistence in Murine Macrophages Impairs IFN-β Response but Not Synthesis.

    PubMed

    Rivera-Toledo, Evelyn; Torres-González, Laura; Gómez, Beatriz

    2015-10-01

    Type-I interferon (IFN-I) production is an early response to viral infection and pathogenic viruses have evolved multiple strategies to evade this cellular defense. Some viruses can establish and maintain persistent infections by altering the IFN-I signaling pathway. Here, we studied IFN-I synthesis and response in an in vitro model of persistent infection by respiratory syncytial virus (RSV) in a murine macrophage-like cell line. In this model, interferon regulatory factor 3 was constitutively active and located at nuclei of persistently infected cells, inducing expression of IFN-beta mRNA and protein. However, persistently infected macrophages did not respond in an autocrine manner to the secreted-IFN-beta or to recombinant-IFN-beta, since phosphorylated-STAT1 was not detected by western blot and transcription of the interferon-stimulated genes (ISGs) Mx1 and ISG56 was not induced. Treatment of non-infected macrophages with supernatants from persistently infected cells induced STAT1 phosphorylation and ISGs expression, mediated by the IFN-I present in the supernatants, because blocking the IFN-I receptor inhibited STAT1 phosphorylation. Results suggest that the lack of autocrine response to IFN-I by the host cell may be one mechanism for maintenance of RSV persistence. Furthermore, STAT1 phosphorylation and ISGs expression induced in non-infected cells by supernatants from persistently infected macrophages suggest that RSV persistence may trigger a proinflammatory phenotype in non-infected cells as part of the pathogenesis of RSV infection. PMID:26501312

  17. Respiratory Syncytial Virus Persistence in Murine Macrophages Impairs IFN-β Response but Not Synthesis

    PubMed Central

    Rivera-Toledo, Evelyn; Torres-González, Laura; Gómez, Beatriz

    2015-01-01

    Type-I interferon (IFN-I) production is an early response to viral infection and pathogenic viruses have evolved multiple strategies to evade this cellular defense. Some viruses can establish and maintain persistent infections by altering the IFN-I signaling pathway. Here, we studied IFN-I synthesis and response in an in vitro model of persistent infection by respiratory syncytial virus (RSV) in a murine macrophage-like cell line. In this model, interferon regulatory factor 3 was constitutively active and located at nuclei of persistently infected cells, inducing expression of IFN-beta mRNA and protein. However, persistently infected macrophages did not respond in an autocrine manner to the secreted-IFN-beta or to recombinant-IFN-beta, since phosphorylated-STAT1 was not detected by western blot and transcription of the interferon-stimulated genes (ISGs) Mx1 and ISG56 was not induced. Treatment of non-infected macrophages with supernatants from persistently infected cells induced STAT1 phosphorylation and ISGs expression, mediated by the IFN-I present in the supernatants, because blocking the IFN-I receptor inhibited STAT1 phosphorylation. Results suggest that the lack of autocrine response to IFN-I by the host cell may be one mechanism for maintenance of RSV persistence. Furthermore, STAT1 phosphorylation and ISGs expression induced in non-infected cells by supernatants from persistently infected macrophages suggest that RSV persistence may trigger a proinflammatory phenotype in non-infected cells as part of the pathogenesis of RSV infection. PMID:26501312

  18. Hepatitis C Virus. Strategies to Evade Antiviral Responses

    PubMed Central

    Gokhale, Nandan S.; Vazquez, Christine; Horner, Stacy M.

    2015-01-01

    Summary Hepatitis C virus (HCV) causes chronic liver disease and poses a major clinical and economic burden worldwide. HCV is an RNA virus that is sensed as non-self in the infected liver by host pattern recognition receptors, triggering downstream signaling to interferons (IFNs). The type III IFNs play an important role in immunity to HCV, and human genetic variation in their gene loci is associated with differential HCV infection outcomes. HCV evades host antiviral innate immune responses to mediate a persistent infection in the liver. This review focuses on anti-HCV innate immune sensing, innate signaling and effectors, and the processes and proteins used by HCV to evade and regulate host innate immunity. PMID:25983854

  19. Non-toxic antimicrobials that evade drug resistance

    PubMed Central

    Davis, Stephen A.; Vincent, Benjamin M.; Endo, Matthew M.; Whitesell, Luke; Marchillo, Karen; Andes, David R.; Lindquist, Susan; Burke, Martin D.

    2015-01-01

    Drugs that act more promiscuously provide fewer routes for the emergence of resistant mutants. But this benefit often comes at the cost of serious off-target and dose-limiting toxicities. The classic example is the antifungal amphotericin B (AmB), which has evaded resistance for more than half a century. We report dramatically less toxic amphotericins that nevertheless evade resistance. They are scalably accessed in just three steps from the natural product, and bind their target (the fungal sterol, ergosterol) with far greater selectivity than AmB. Hence, they are less toxic and far more effective in a mouse model of systemic candidiasis. Surprisingly, exhaustive efforts to select for mutants resistant to these more selective compounds revealed that they are just as impervious to resistance as AmB. Thus, highly selective cytocidal action and the evasion of resistance are not mutually exclusive, suggesting practical routes to the discovery of less toxic, resistance-evasive therapies. PMID:26030729

  20. Efficient natural defense mechanisms against Listeria monocytogenes in T and B cell-deficient allogeneic bone marrow radiation chimeras. Preactivated macrophages are the main effector cells in an early phase after bone marrow transfer

    SciTech Connect

    Roesler, J.; Groettrup, E.B.; Baccarini, M.; Lohmann-Mattes, M.L. )

    1989-09-01

    Radiation chimeras in the early phase after bone marrow transplantation are a good model to study the efficiency of the body's nonspecific defense system represented by macrophages (M phi), polymorphonuclear cells (PMN), and NK cells. These cell types are present in large numbers in spleen and liver at that time, whereas the specific immune system represented by T and B cells is functionally deficient. We previously reported enhanced activities in vitro of M phi (and PMN) from recipient animals in an early phase after allogeneic bone marrow transfer. We here demonstrate that these activities result in enhanced spontaneous resistance against Listeria monocytogenes in vivo: CFU of L. monocytogenes in spleen and liver 48 h after infection were about 1 or 2 to 4 log steps less than in untreated control mice of donor or host haplotype. This enhanced resistance decreased over the 4-mo period after marrow transfer. Preactivated M phi were identified as the most important effector cells. Isolated from spleen and peritoneal cavity, they performed enhanced killing of phagocytosed Listeria. Such preactivated M phi occurred in recipient animals after transfer of allogeneic but not of syngeneic bone marrow. The precise mechanism of M phi activation in the allogeneic radiation chimera in the complete absence of any detectable T cell function is not clear at present. However, these preactivated M phi display an important protective effect against L. monocytogenes: chimeras could eliminate Listeria without acquisition of positive delayed-type sensitivity when infected with 10(3) bacteria. An inoculum of 5 . 10(3) L. monocytogenes resulted either in prolonged survival compared with normal mice of the recipient haplotype or in definitive survival accompanied by a positive delayed-type sensitivity.

  1. [Pharmacological properties of law-evading chemical substances].

    PubMed

    Funada, Masahiko

    2015-09-01

    In recent years, frequent cases of people suffering disturbed consciousness, dyspnea, etc. due to abuse of synthetic cannabis and being transported by ambulance or causing traffic accidents are occurring and are becoming a serious social problem in Japan. Most law-evading herbal products have colorful illustrations and logos and are sold as incense or herbs. Law-evading herbal products consist of finely chopped dry vegetative matter mixed with chemical substances (drugs), and the drugs are injurious to health. Analysis of chemical substances in herbal products clarified that they contain synthetic cannabinoid, a chemical component that exhibits action similar to that of hemp. There are many affinity compounds of cannabinoid, so presently, even if a particular drug is regulated, similar compounds that partially differ in structure will propagate. There is thus a cat-and-mouse game between regulations on chemical substances and their propagation. This paper summarizes the pharmacological actions and danger of chemical substances contained in law-evading herbal products by focusing on synthetic cannabinoid or synthetic cathinone, a chemical substance it contains. PMID:26394508

  2. Sterile-α- and armadillo motif-containing protein inhibits the TRIF-dependent downregulation of signal regulatory protein α to interfere with intracellular bacterial elimination in Burkholderia pseudomallei-infected mouse macrophages.

    PubMed

    Baral, Pankaj; Utaisincharoen, Pongsak

    2013-09-01

    Burkholderia pseudomallei, the causative agent of melioidosis, evades macrophage killing by suppressing the TRIF-dependent pathway, leading to inhibition of inducible nitric oxide synthase (iNOS) expression. We previously demonstrated that virulent wild-type B. pseudomallei inhibits the TRIF-dependent pathway by upregulating sterile-α- and armadillo motif-containing protein (SARM) and by inhibiting downregulation of signal regulatory protein α (SIRPα); both molecules are negative regulators of Toll-like receptor signaling. In contrast, the less virulent lipopolysaccharide (LPS) mutant of B. pseudomallei is unable to exhibit these features and is susceptible to macrophage killing. However, the functional relationship of these two negative regulators in the evasion of macrophage defense has not been elucidated. We demonstrated here that SIRPα downregulation was observed after inhibition of SARM expression by small interfering RNA in wild-type-infected macrophages, indicating that SIRPα downregulation is regulated by SARM. Furthermore, this downregulation requires activation of the TRIF signaling pathway, as we observed abrogation of SIRPα downregulation as well as restricted bacterial growth in LPS mutant-infected TRIF-depleted macrophages. Although inhibition of SARM expression is correlated to SIRPα downregulation and iNOS upregulation in gamma interferon-activated wild-type-infected macrophages, these phenomena appear to bypass the TRIF-dependent pathway. Similar to live bacteria, the wild-type LPS is able to upregulate SARM and to prevent SIRPα downregulation, implying that the LPS of B. pseudomallei may play a crucial role in regulating the expression of these two negative regulators. Altogether, our findings show a previously unrecognized role of B. pseudomallei-induced SARM in inhibiting SIRPα downregulation-mediated iNOS upregulation, facilitating the ability of the bacterium to multiply in macrophages. PMID:23836818

  3. Gaining insight into soybean defense responses using functional genomics approaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean pathogens significantly impact yield, resulting in over 4 billion dollars in lost revenue annually in the United States alone as a result of disease. Despite the deployment of improved soybean cultivars, pathogens continue to evolve to evade plant defense responses. Thus, there is an urgent ...

  4. Surface modification of nanoparticles enables selective evasion of phagocytic clearance by distinct macrophage phenotypes

    NASA Astrophysics Data System (ADS)

    Qie, Yaqing; Yuan, Hengfeng; von Roemeling, Christina A.; Chen, Yuanxin; Liu, Xiujie; Shih, Kevin D.; Knight, Joshua A.; Tun, Han W.; Wharen, Robert E.; Jiang, Wen; Kim, Betty Y. S.

    2016-05-01

    Nanomedicine is a burgeoning industry but an understanding of the interaction of nanomaterials with the immune system is critical for clinical translation. Macrophages play a fundamental role in the immune system by engulfing foreign particulates such as nanoparticles. When activated, macrophages form distinct phenotypic populations with unique immune functions, however the mechanism by which these polarized macrophages react to nanoparticles is unclear. Furthermore, strategies to selectively evade activated macrophage subpopulations are lacking. Here we demonstrate that stimulated macrophages possess higher phagocytic activities and that classically activated (M1) macrophages exhibit greater phagocytic capacity than alternatively activated (M2) macrophages. We show that modification of nanoparticles with polyethylene-glycol results in decreased clearance by all macrophage phenotypes, but importantly, coating nanoparticles with CD47 preferentially lowers phagocytic activity by the M1 phenotype. These results suggest that bio-inspired nanoparticle surface design may enable evasion of specific components of the immune system and provide a rational approach for developing immune tolerant nanomedicines.

  5. Cronobacter sakazakii clinical isolates overcome host barriers and evade the immune response.

    PubMed

    Almajed, Faisal S; Forsythe, Stephen J

    2016-01-01

    Cronobacter sakazakii is the most frequently clinically isolated species of the Cronobacter genus. However the virulence factors of C. sakazakii including their ability to overcome host barriers remains poorly studied. In this study, ten clinical isolates of C. sakazakii were assessed for their ability to invade and translocate through human colonic carcinoma epithelial cells (Caco-2) and human brain microvascular endothelial cells (HBMEC). Their ability to avoid phagocytosis in human macrophages U937 and human brain microglial cells was investigated. Additionally, they were tested for serum sensitivity and the presence of the Cronobacter plasminogen activation gene (cpa) gene, which is reported to confer serum resistance. Our data showed that the clinical C. sakazakii strains invaded and translocated through Caco-2 and HBMEC cell lines and some strains showed significantly higher levels of invasion and translocation. Moreover, C. sakazakii was able to persist and even multiply in phagocytic macrophage and microglial cells. All strains, except one, were able to withstand human serum exposure, the single serum sensitive strain was also the only one which did not encode for the cpa gene. These results demonstrate that C. sakazakii clinical isolates are able to overcome host barriers and evade the host immune response indicating their capacity to cause diseases such as necrotizing enterocolitis (NEC) and meningitis. Our data showed for the first time the ability of C. sakazakii clinical isolates to survive and multiply within human microglial cells. Additionally, it was shown that C. sakazakii clinical strains have the capacity to translocate through the Caco-2 and HBMEC cell lines paracellularly. PMID:26616163

  6. Stealth nanotubes: strategies of shielding carbon nanotubes to evade opsonization and improve biodistribution

    PubMed Central

    Kotagiri, Nalinikanth; Kim, Jin-Woo

    2014-01-01

    Carbon nanotubes (CNTs) have recently been in the limelight for their potential role in disease diagnostics and therapeutics, as well as in tissue engineering. Before these medical applications can be realized, there is a need to address issues like opsonization, phagocytosis by macrophages, and sequestration to the liver and spleen for eventual elimination from the body; along with equally important issues such as aqueous solubility, dispersion, biocompatibility, and biofunctionalization. CNTs have not been shown to be able to evade such biological obstacles, which include their nonspecific attachments to cells and other biological components in the bloodstream, before reaching target tissues and cells in vivo. This will eventually determine their longevity in circulation and clearance rate from the body. This review article discusses the current status, challenges, practical strategies, and implementations of coating CNTs with biocompatible and opsonin-resistant moieties, rendering CNTs transparent to opsonins and deceiving the innate immune response to make believe that the CNTs are not foreign. A holistic approach to the development of such “stealth” CNTs is presented, which encompasses not only several biophysicochemical factors that are not limited to surface treatment of CNTs, but also extraneous biological factors such as the protein corona formation that inevitably controls the in vivo fate of the particles. This review also discusses the present and potential applications, along with the future directions, of CNTs and their hybrid-based nanotheranostic agents for multiplex, multimodal molecular imaging and therapy, as well as in other applications, such as drug delivery and tissue engineering. PMID:24872705

  7. Stealth nanotubes: strategies of shielding carbon nanotubes to evade opsonization and improve biodistribution.

    PubMed

    Kotagiri, Nalinikanth; Kim, Jin-Woo

    2014-01-01

    Carbon nanotubes (CNTs) have recently been in the limelight for their potential role in disease diagnostics and therapeutics, as well as in tissue engineering. Before these medical applications can be realized, there is a need to address issues like opsonization, phagocytosis by macrophages, and sequestration to the liver and spleen for eventual elimination from the body; along with equally important issues such as aqueous solubility, dispersion, biocompatibility, and biofunctionalization. CNTs have not been shown to be able to evade such biological obstacles, which include their nonspecific attachments to cells and other biological components in the bloodstream, before reaching target tissues and cells in vivo. This will eventually determine their longevity in circulation and clearance rate from the body. This review article discusses the current status, challenges, practical strategies, and implementations of coating CNTs with biocompatible and opsonin-resistant moieties, rendering CNTs transparent to opsonins and deceiving the innate immune response to make believe that the CNTs are not foreign. A holistic approach to the development of such "stealth" CNTs is presented, which encompasses not only several biophysicochemical factors that are not limited to surface treatment of CNTs, but also extraneous biological factors such as the protein corona formation that inevitably controls the in vivo fate of the particles. This review also discusses the present and potential applications, along with the future directions, of CNTs and their hybrid-based nanotheranostic agents for multiplex, multimodal molecular imaging and therapy, as well as in other applications, such as drug delivery and tissue engineering. PMID:24872705

  8. Zebrafish larvae evade predators by sensing water flow.

    PubMed

    Stewart, William J; Cardenas, Gilberto S; McHenry, Matthew J

    2013-02-01

    The ability of fish to evade predators is central to the ecology and evolution of a diversity of species. However, it is largely unclear how prey fish detect predators in order to initiate their escape. We tested whether larval zebrafish (Danio rerio) sense the flow created by adult predators of the same species. When placed together in a cylindrical arena, we found that larvae were able to escape 70% of predator strikes (mean escape probability P(escape)=0.7, N=13). However, when we pharmacologically ablated the flow-sensitive lateral line system, larvae were rarely capable of escape (mean P(escape)=0.05, N=11). In order to explore the rapid events that facilitate a successful escape, we recorded freely swimming predators and prey using a custom-built camera dolly. This device permitted two-dimensional camera motion to manually track prey and record their escape response with high temporal and spatial resolution. These recordings demonstrated that prey were more than 3 times more likely to evade a suction-feeding predator if they responded before (P(escape)=0.53, N=43), rather than after (P(escape)=0.15, N=13), a predator's mouth opened, which is a highly significant difference. Therefore, flow sensing plays an essential role in predator evasion by facilitating a response prior to a predator's strike. PMID:23325859

  9. Pyoverdine, the Major Siderophore in Pseudomonas aeruginosa, Evades NGAL Recognition

    PubMed Central

    Peek, Mary E.; Bhatnagar, Abhinav; McCarty, Nael A.; Zughaier, Susu M.

    2012-01-01

    Pseudomonas aeruginosa is the most common pathogen that persists in the cystic fibrosis lungs. Bacteria such as P. aeruginosa secrete siderophores (iron-chelating molecules) and the host limits bacterial growth by producing neutrophil-gelatinase-associated lipocalin (NGAL) that specifically scavenges bacterial siderophores, therefore preventing bacteria from establishing infection. P. aeruginosa produces a major siderophore known as pyoverdine, found to be important for bacterial virulence and biofilm development. We report that pyoverdine did not bind to NGAL, as measured by tryptophan fluorescence quenching, while enterobactin bound to NGAL effectively causing a strong response. The experimental data indicate that pyoverdine evades NGAL recognition. We then employed a molecular modeling approach to simulate the binding of pyoverdine to human NGAL using NGAL's published crystal structures. The docking of pyoverdine to NGAL predicted nine different docking positions; however, neither apo- nor ferric forms of pyoverdine docked into the ligand-binding site in the calyx of NGAL where siderophores are known to bind. The molecular modeling results offer structural support that pyoverdine does not bind to NGAL, confirming the results obtained in the tryptophan quenching assay. The data suggest that pyoverdine is a stealth siderophore that evades NGAL recognition allowing P. aeruginosa to establish chronic infections in CF lungs. PMID:22973307

  10. Pyoverdine, the Major Siderophore in Pseudomonas aeruginosa, Evades NGAL Recognition.

    PubMed

    Peek, Mary E; Bhatnagar, Abhinav; McCarty, Nael A; Zughaier, Susu M

    2012-01-01

    Pseudomonas aeruginosa is the most common pathogen that persists in the cystic fibrosis lungs. Bacteria such as P. aeruginosa secrete siderophores (iron-chelating molecules) and the host limits bacterial growth by producing neutrophil-gelatinase-associated lipocalin (NGAL) that specifically scavenges bacterial siderophores, therefore preventing bacteria from establishing infection. P. aeruginosa produces a major siderophore known as pyoverdine, found to be important for bacterial virulence and biofilm development. We report that pyoverdine did not bind to NGAL, as measured by tryptophan fluorescence quenching, while enterobactin bound to NGAL effectively causing a strong response. The experimental data indicate that pyoverdine evades NGAL recognition. We then employed a molecular modeling approach to simulate the binding of pyoverdine to human NGAL using NGAL's published crystal structures. The docking of pyoverdine to NGAL predicted nine different docking positions; however, neither apo- nor ferric forms of pyoverdine docked into the ligand-binding site in the calyx of NGAL where siderophores are known to bind. The molecular modeling results offer structural support that pyoverdine does not bind to NGAL, confirming the results obtained in the tryptophan quenching assay. The data suggest that pyoverdine is a stealth siderophore that evades NGAL recognition allowing P. aeruginosa to establish chronic infections in CF lungs. PMID:22973307

  11. Suboptimal period design for a maneuvering missile to evade tracking filters

    NASA Astrophysics Data System (ADS)

    Lai, Lin-Ying

    1988-06-01

    The engagement between an antiship missile and a ship's defence system is investigated. The missile is equipped with proportional navigation guidance for homing in on its ship target. The ship's defense system consists of a radar, an estimation system (the extended Kalman filter and the jump filter are used), and a gun system. The performance index is defined as the estimated number of hits (EHITS) of projectiles on the missile. The main objective is to determine maneuvering periods for the missile which minimize the EHITS to evade the ship's gunfire under different engagement conditions. The maneuvering periods are design parameters in the missile's controls of both the vertical and the horizontal planes. The engagement conditions are as follows: the maximum amplitude of the maneuvering functions, the homing in position of the missile on the ship, the measurement noise condition of the ship's radar, and the missile's model assumed in the ship's filters. The missile's control functions considered are periodic and of specific types (sinusoidal, square and sawtooth waveforms); therefore, the periods which minimize the EHITS in this study are suboptimal for the general engagement problem. Two methods are used to obtain the suboptimal periods: one is the brute force method of computing the EHITS for certain equally spaced periods, the other uses an optimization software to search for the minimum point.

  12. Macrophage phagocytosis: effects of environmental pollutants, alcohol, cigarette smoke, and other external factors

    PubMed Central

    Karavitis, John; Kovacs, Elizabeth J.

    2011-01-01

    The ability of a pathogen to evade host immunity successfully, in contrast to the host's capacity to defend itself against a foreign invader, is a complex struggle, in which eradication of infection is dictated by a robust immunologic response. Often, there are external factors that can alter the outcome by tipping the scale to benefit pathogen establishment rather than resolution by the host's defense system. These external sources, such a cigarettes, alcohol, or environmental pollutants, can negatively influence the effectiveness of the immune system's response to a pathogen. The observed suppression of immune function can be attributed to dysregulated cytokine and chemokine production, the loss of migratory potential, or the inability to phagocytose pathogens by immune cells. This review will focus on the mechanisms involved during the toxin-induced suppression of phagocytosis. The accumulated data support the importance of studying the mechanisms of phagocytosis following exposure to these factors, in that this effect alone cannot only leave the host susceptible to infection but also promote alterations in many other macrophage functions necessary for pathogen clearance and restoration of homeostasis. PMID:21878544

  13. *Ambient Particluate Matter Supresses Alveolar Macrophage Cytokine Response to Lipopolysaccharide

    EPA Science Inventory

    Reports link ambient particulate matter (PM) exposure with cardiopulmonary mortality and morbidity, including the exacerbation of inflammatory disease and increased hospitalization for lung infections. Alveolar macrophages (AM) play an important defense role against infections v...

  14. A simple motion differential game with different constraints on controls and under phase constraint on the state of the evader

    NASA Astrophysics Data System (ADS)

    Rakhmanov, Askar; Ibragimov, Gafurjan

    2016-06-01

    We consider a simple motion pursuit differential game of one pursuer and one evader. Control of the pursuer is subjected to integral constraint, and that of the evader is subjected to geometric constraint. More precisely, value of control parameter of the evader belongs to a given convex subset of ℝn. Pursuit is completed if the evader becomes in l vicinity of the pursuer. Sufficient conditions of completion of pursuit are obtained.

  15. Improved Method for Culturing Guinea-Pig Macrophage Cells

    NASA Technical Reports Server (NTRS)

    Savage, J.

    1982-01-01

    Proper nutrients and periodic changes in culture medium maintain cell viability for a longer period. New method uses a thioglycolate solution, instead of mineral oil, to induce macrophage cells in guinea pigs and also uses an increased percent of fetal-calf bovine serum in cultivation medium. Macrophage cells play significant roles in the body's healing and defense systems.

  16. Fungal biosynthesis of the bibenzoquinone oosporein to evade insect immunity

    PubMed Central

    Feng, Peng; Shang, Yanfang; Cen, Kai; Wang, Chengshu

    2015-01-01

    Quinones are widely distributed in nature and exhibit diverse biological or pharmacological activities; however, their biosynthetic machineries are largely unknown. The bibenzoquinone oosporein was first identified from the ascomycete insect pathogen Beauveria bassiana >50 y ago. The toxin can also be produced by different plant pathogenic and endophytic fungi with an array of biological activities. Here, we report the oosporein biosynthetic machinery in fungi, a polyketide synthase (PKS) pathway including seven genes for quinone biosynthesis. The PKS oosporein synthase 1 (OpS1) produces orsellinic acid that is hydroxylated to benzenetriol by the hydroxylase OpS4. The intermediate is oxidized either nonenzymatically to 5,5′-dideoxy-oosporein or enzymatically to benzenetetrol by the putative dioxygenase OpS7. The latter is further dimerized to oosporein by the catalase OpS5. The transcription factor OpS3 regulates intrapathway gene expression. Insect bioassays revealed that oosporein is required for fungal virulence and acts by evading host immunity to facilitate fungal multiplication in insects. These results contribute to the known mechanisms of quinone biosynthesis and the understanding of small molecules deployed by fungi that interact with their hosts. PMID:26305932

  17. Pathogenic Chikungunya Virus Evades B Cell Responses to Establish Persistence.

    PubMed

    Hawman, David W; Fox, Julie M; Ashbrook, Alison W; May, Nicholas A; Schroeder, Kristin M S; Torres, Raul M; Crowe, James E; Dermody, Terence S; Diamond, Michael S; Morrison, Thomas E

    2016-08-01

    Chikungunya virus (CHIKV) and related alphaviruses cause epidemics of acute and chronic musculoskeletal disease. To investigate the mechanisms underlying the failure of immune clearance of CHIKV, we studied mice infected with an attenuated CHIKV strain (181/25) and the pathogenic parental strain (AF15561), which differ by five amino acids. Whereas AF15561 infection of wild-type mice results in viral persistence in joint tissues, 181/25 is cleared. In contrast, 181/25 infection of μMT mice lacking mature B cells results in viral persistence in joint tissues, suggesting that virus-specific antibody is required for clearance of infection. Mapping studies demonstrated that a highly conserved glycine at position 82 in the A domain of the E2 glycoprotein impedes clearance and neutralization of multiple CHIKV strains. Remarkably, murine and human antibodies targeting E2 domain B failed to neutralize pathogenic CHIKV strains efficiently. Our data suggest that pathogenic CHIKV strains evade E2 domain-B-neutralizing antibodies to establish persistence. PMID:27452455

  18. Parasitic Cape honeybee workers, Apis mellifera capensis, evade policing

    NASA Astrophysics Data System (ADS)

    Martin, Stephen J.; Beekman, Madeleine; Wossler, Theresa C.; Ratnieks, Francis L. W.

    2002-01-01

    Relocation of the Cape honeybee, Apis mellifera capensis, by bee-keepers from southern to northern South Africa in 1990 has caused widespread death of managed African honeybee, A. m. scutellata, colonies. Apis mellifera capensis worker bees are able to lay diploid, female eggs without mating by means of automictic thelytoky (meiosis followed by fusion of two meiotic products to restore egg diploidy), whereas workers of other honeybee subspecies are able to lay only haploid, male eggs. The A. m. capensis workers, which are parasitizing and killing A. m. scutellata colonies in northern South Africa, are the asexual offspring of a single, original worker in which the small amount of genetic variation observed is due to crossing over during meiosis (P. Kryger, personal communication). Here we elucidate two principal mechanisms underlying this parasitism. Parasitic A. m. capensis workers activate their ovaries in host colonies that have a queen present (queenright colonies), and they lay eggs that evade being killed by other workers (worker policing)-the normal fate of worker-laid eggs in colonies with a queen. This unique parasitism by workers is an instance in which a society is unable to control the selfish actions of its members.

  19. Genetically Enhanced Lysozyme Evades a Pathogen Derived Inhibitory Protein

    PubMed Central

    Dostal, Sarah M.; Fang, Yongliang; Guerrette, Jonathan C.; Scanlon, Thomas C.; Griswold, Karl E.

    2015-01-01

    The accelerating spread of drug-resistant bacteria is creating demand for novel antibiotics. Bactericidal enzymes, such as human lysozyme (hLYZ), are interesting drug candidates due to their inherent catalytic nature and lack of susceptibility to the resistance mechanisms typically directed towards chemotherapeutics. However, natural antibacterial enzymes have their own limitations. For example, hLYZ is susceptible to pathogen derived inhibitory proteins, such as Escherichia coli Ivy. Here, we describe proof of concept studies demonstrating that hLYZ can be effectively redesigned to evade this potent lysozyme inhibitor. Large combinatorial libraries of hLYZ were analyzed using an innovative screening platform based on microbial co-culture in hydrogel microdroplets. Isolated hLYZ variants were orders of magnitude less susceptible to E. coli Ivy yet retained high catalytic proficiency and inherent antibacterial activity. Interestingly, the engineered escape variants showed a disadvantageous increase in susceptibility to the related Ivy ortholog from Pseudomonas aeruginosa as well as an unrelated E. coli inhibitory protein, MliC. Thus, while we have achieved our original objective with respect to escaping E. coli Ivy, engineering hLYZ for broad-spectrum evasion of proteinaceous inhibitors will require consideration of the complex and varied determinants that underlie molecular recognition by these emerging virulence factors. PMID:25607237

  20. Fungal biosynthesis of the bibenzoquinone oosporein to evade insect immunity.

    PubMed

    Feng, Peng; Shang, Yanfang; Cen, Kai; Wang, Chengshu

    2015-09-01

    Quinones are widely distributed in nature and exhibit diverse biological or pharmacological activities; however, their biosynthetic machineries are largely unknown. The bibenzoquinone oosporein was first identified from the ascomycete insect pathogen Beauveria bassiana>50 y ago. The toxin can also be produced by different plant pathogenic and endophytic fungi with an array of biological activities. Here, we report the oosporein biosynthetic machinery in fungi, a polyketide synthase (PKS) pathway including seven genes for quinone biosynthesis. The PKS oosporein synthase 1 (OpS1) produces orsellinic acid that is hydroxylated to benzenetriol by the hydroxylase OpS4. The intermediate is oxidized either nonenzymatically to 5,5'-dideoxy-oosporein or enzymatically to benzenetetrol by the putative dioxygenase OpS7. The latter is further dimerized to oosporein by the catalase OpS5. The transcription factor OpS3 regulates intrapathway gene expression. Insect bioassays revealed that oosporein is required for fungal virulence and acts by evading host immunity to facilitate fungal multiplication in insects. These results contribute to the known mechanisms of quinone biosynthesis and the understanding of small molecules deployed by fungi that interact with their hosts. PMID:26305932

  1. Parasitic Cape honeybee workers, Apis mellifera capensis, evade policing.

    PubMed

    Martin, Stephen J; Beekman, Madeleine; Wossler, Theresa C; Ratnieks, Francis L W

    2002-01-10

    Relocation of the Cape honeybee, Apis mellifera capensis, by bee-keepers from southern to northern South Africa in 1990 has caused widespread death of managed African honeybee, A. m. scutellata, colonies. Apis mellifera capensis worker bees are able to lay diploid, female eggs without mating by means of automictic thelytoky (meiosis followed by fusion of two meiotic products to restore egg diploidy), whereas workers of other honeybee subspecies are able to lay only haploid, male eggs. The A. m. capensis workers, which are parasitizing and killing A. m. scutellata colonies in northern South Africa, are the asexual offspring of a single, original worker in which the small amount of genetic variation observed is due to crossing over during meiosis (P. Kryger, personal communication). Here we elucidate two principal mechanisms underlying this parasitism. Parasitic A. m. capensis workers activate their ovaries in host colonies that have a queen present (queenright colonies), and they lay eggs that evade being killed by other workers (worker policing)-the normal fate of worker-laid eggs in colonies with a queen. This unique parasitism by workers is an instance in which a society is unable to control the selfish actions of its members. PMID:11805832

  2. Defense mechanisms of the respiratory membrane.

    PubMed

    Green, G M; Jakab, G J; Low, R B; Davis, G S

    1977-03-01

    The success or failure of pulmonary defense mechanisms largely determines the appearance of clinical lung disease. The lung is protected by interlucking systems of nonspecific and specific defenses. Inhaled substrances can be isolated by mechanical barriers or can be physically removed from the lung either by transport up the bronchial mucociliary escalator or by transport through interstitial and lymphatic channels leading to lymph nodes. Substances can be locally detoxified within the lung by interaction with secretory proteins, such as antibodies, or by neutralization and dissolution within phagocytic cells. The pulmonary alveolar macrophage is the central figure in the protection of the respiratory membrane, operating in all 3 of the nonspecific modes of defense and augmented by specific immunologic mechanisms as well. Alterations in macrophage function and physiology may be crucial in determining the effectiveness of pulmonary defense. Recent advances in the cell biology of the alveolar macrophage have led to a greater understanding of its complex funcition. The multiple origins of macrophages from local and circulating cell pools and the variability in their fate and lifespan reflect the multi-faceted role of this cell type. The importance of the interactions between macrophages, orther lung cells, and other defense mechanisms has become increasingly clear. As well as functioning as resident defender of the alveolus, the macrophage is an important effector of the pulmonary immune response and plays a key role in the pathogenesis of a wide variety of inflammatory, destructive, and fibrotic lung diseases. Humoral and cell-mediated immune responses amplify and direct lung defenses against infection and may also participate in protection against other agents. Immunoglobulin A and G, microbial neutralizing and opsonizing anti-bodies, and macrophage-stimulating T lymphocytes are the major immunospecific forms of lung defense. Infectious agents, cigarette smoke, air

  3. Herbivore exploits orally secreted bacteria to suppress plant defenses

    PubMed Central

    Chung, Seung Ho; Rosa, Cristina; Scully, Erin D.; Peiffer, Michelle; Tooker, John F.; Hoover, Kelli; Luthe, Dawn S.; Felton, Gary W.

    2013-01-01

    Induced plant defenses in response to herbivore attack are modulated by cross-talk between jasmonic acid (JA)- and salicylic acid (SA)-signaling pathways. Oral secretions from some insect herbivores contain effectors that overcome these antiherbivore defenses. Herbivores possess diverse microbes in their digestive systems and these microbial symbionts can modify plant–insect interactions; however, the specific role of herbivore-associated microbes in manipulating plant defenses remains unclear. Here, we demonstrate that Colorado potato beetle (Leptinotarsa decemlineata) larvae exploit bacteria in their oral secretions to suppress antiherbivore defenses in tomato (Solanum lycopersicum). We found that antibiotic-untreated larvae decreased production of JA and JA-responsive antiherbivore defenses, but increased SA accumulation and SA-responsive gene expression. Beetles benefit from down-regulating plant defenses by exhibiting enhanced larval growth. In SA-deficient plants, suppression was not observed, indicating that suppression of JA-regulated defenses depends on the SA-signaling pathway. Applying bacteria isolated from larval oral secretions to wounded plants confirmed that three microbial symbionts belonging to the genera Stenotrophomonas, Pseudomonas, and Enterobacter are responsible for defense suppression. Additionally, reinoculation of these bacteria to antibiotic-treated larvae restored their ability to suppress defenses. Flagellin isolated from Pseudomonas sp. was associated with defense suppression. Our findings show that the herbivore exploits symbiotic bacteria as a decoy to deceive plants into incorrectly perceiving the threat as microbial. By interfering with the normal perception of herbivory, beetles can evade antiherbivore defenses of its host. PMID:24019469

  4. Herbivore exploits orally secreted bacteria to suppress plant defenses.

    PubMed

    Chung, Seung Ho; Rosa, Cristina; Scully, Erin D; Peiffer, Michelle; Tooker, John F; Hoover, Kelli; Luthe, Dawn S; Felton, Gary W

    2013-09-24

    Induced plant defenses in response to herbivore attack are modulated by cross-talk between jasmonic acid (JA)- and salicylic acid (SA)-signaling pathways. Oral secretions from some insect herbivores contain effectors that overcome these antiherbivore defenses. Herbivores possess diverse microbes in their digestive systems and these microbial symbionts can modify plant-insect interactions; however, the specific role of herbivore-associated microbes in manipulating plant defenses remains unclear. Here, we demonstrate that Colorado potato beetle (Leptinotarsa decemlineata) larvae exploit bacteria in their oral secretions to suppress antiherbivore defenses in tomato (Solanum lycopersicum). We found that antibiotic-untreated larvae decreased production of JA and JA-responsive antiherbivore defenses, but increased SA accumulation and SA-responsive gene expression. Beetles benefit from down-regulating plant defenses by exhibiting enhanced larval growth. In SA-deficient plants, suppression was not observed, indicating that suppression of JA-regulated defenses depends on the SA-signaling pathway. Applying bacteria isolated from larval oral secretions to wounded plants confirmed that three microbial symbionts belonging to the genera Stenotrophomonas, Pseudomonas, and Enterobacter are responsible for defense suppression. Additionally, reinoculation of these bacteria to antibiotic-treated larvae restored their ability to suppress defenses. Flagellin isolated from Pseudomonas sp. was associated with defense suppression. Our findings show that the herbivore exploits symbiotic bacteria as a decoy to deceive plants into incorrectly perceiving the threat as microbial. By interfering with the normal perception of herbivory, beetles can evade antiherbivore defenses of its host. PMID:24019469

  5. HIV-1 evades innate immune recognition through specific cofactor recruitment

    NASA Astrophysics Data System (ADS)

    Rasaiyaah, Jane; Tan, Choon Ping; Fletcher, Adam J.; Price, Amanda J.; Blondeau, Caroline; Hilditch, Laura; Jacques, David A.; Selwood, David L.; James, Leo C.; Noursadeghi, Mahdad; Towers, Greg J.

    2013-11-01

    Human immunodeficiency virus (HIV)-1 is able to replicate in primary human macrophages without stimulating innate immunity despite reverse transcription of genomic RNA into double-stranded DNA, an activity that might be expected to trigger innate pattern recognition receptors. We reasoned that if correctly orchestrated HIV-1 uncoating and nuclear entry is important for evasion of innate sensors then manipulation of specific interactions between HIV-1 capsid and host factors that putatively regulate these processes should trigger pattern recognition receptors and stimulate type 1 interferon (IFN) secretion. Here we show that HIV-1 capsid mutants N74D and P90A, which are impaired for interaction with cofactors cleavage and polyadenylation specificity factor subunit 6 (CPSF6) and cyclophilins (Nup358 and CypA), respectively, cannot replicate in primary human monocyte-derived macrophages because they trigger innate sensors leading to nuclear translocation of NF-κB and IRF3, the production of soluble type 1 IFN and induction of an antiviral state. Depletion of CPSF6 with short hairpin RNA expression allows wild-type virus to trigger innate sensors and IFN production. In each case, suppressed replication is rescued by IFN-receptor blockade, demonstrating a role for IFN in restriction. IFN production is dependent on viral reverse transcription but not integration, indicating that a viral reverse transcription product comprises the HIV-1 pathogen-associated molecular pattern. Finally, we show that we can pharmacologically induce wild-type HIV-1 infection to stimulate IFN secretion and an antiviral state using a non-immunosuppressive cyclosporine analogue. We conclude that HIV-1 has evolved to use CPSF6 and cyclophilins to cloak its replication, allowing evasion of innate immune sensors and induction of a cell-autonomous innate immune response in primary human macrophages.

  6. HIV-1 evades innate immune recognition through specific cofactor recruitment.

    PubMed

    Rasaiyaah, Jane; Tan, Choon Ping; Fletcher, Adam J; Price, Amanda J; Blondeau, Caroline; Hilditch, Laura; Jacques, David A; Selwood, David L; James, Leo C; Noursadeghi, Mahdad; Towers, Greg J

    2013-11-21

    Human immunodeficiency virus (HIV)-1 is able to replicate in primary human macrophages without stimulating innate immunity despite reverse transcription of genomic RNA into double-stranded DNA, an activity that might be expected to trigger innate pattern recognition receptors. We reasoned that if correctly orchestrated HIV-1 uncoating and nuclear entry is important for evasion of innate sensors then manipulation of specific interactions between HIV-1 capsid and host factors that putatively regulate these processes should trigger pattern recognition receptors and stimulate type 1 interferon (IFN) secretion. Here we show that HIV-1 capsid mutants N74D and P90A, which are impaired for interaction with cofactors cleavage and polyadenylation specificity factor subunit 6 (CPSF6) and cyclophilins (Nup358 and CypA), respectively, cannot replicate in primary human monocyte-derived macrophages because they trigger innate sensors leading to nuclear translocation of NF-κB and IRF3, the production of soluble type 1 IFN and induction of an antiviral state. Depletion of CPSF6 with short hairpin RNA expression allows wild-type virus to trigger innate sensors and IFN production. In each case, suppressed replication is rescued by IFN-receptor blockade, demonstrating a role for IFN in restriction. IFN production is dependent on viral reverse transcription but not integration, indicating that a viral reverse transcription product comprises the HIV-1 pathogen-associated molecular pattern. Finally, we show that we can pharmacologically induce wild-type HIV-1 infection to stimulate IFN secretion and an antiviral state using a non-immunosuppressive cyclosporine analogue. We conclude that HIV-1 has evolved to use CPSF6 and cyclophilins to cloak its replication, allowing evasion of innate immune sensors and induction of a cell-autonomous innate immune response in primary human macrophages. PMID:24196705

  7. The Tuberculosis Necrotizing Toxin kills macrophages by hydrolyzing NAD

    PubMed Central

    Sun, Jim; Siroy, Axel; Lokareddy, Ravi K.; Speer, Alexander; Doornbos, Kathryn S.; Cingolani, Gino; Niederweis, Michael

    2015-01-01

    Mycobacterium tuberculosis (Mtb) induces necrosis of infected cells to evade immune responses. Recently, we found that Mtb utilizes the protein CpnT to kill human macrophages by secreting its C-terminal domain, named tuberculosis necrotizing toxin (TNT) that induces necrosis by an unknown mechanism. Here we show that TNT gains access to the cytosol of Mtb-infected macrophages, where it hydrolyzes the essential co-enzyme nicotinamide adenine dinucleotide (NAD+). Expression or injection of a non-catalytic TNT mutant showed no cytotoxicity in macrophages or zebrafish zygotes, respectively, demonstrating that the NAD+-glycohydrolase activity is required for TNT-induced cell death. To prevent self-poisoning, Mtb produces an immunity factor for TNT (IFT) that binds TNT and inhibits its activity. The crystal structure of the TNT-IFT complex revealed a novel NAD+-glycohydrolase fold of TNT, which constitutes the founding member of a toxin family wide-spread in pathogenic microorganisms. PMID:26237511

  8. The tuberculosis necrotizing toxin kills macrophages by hydrolyzing NAD.

    PubMed

    Sun, Jim; Siroy, Axel; Lokareddy, Ravi K; Speer, Alexander; Doornbos, Kathryn S; Cingolani, Gino; Niederweis, Michael

    2015-09-01

    Mycobacterium tuberculosis (Mtb) induces necrosis of infected cells to evade immune responses. Recently, we found that Mtb uses the protein CpnT to kill human macrophages by secreting its C-terminal domain, named tuberculosis necrotizing toxin (TNT), which induces necrosis by an unknown mechanism. Here we show that TNT gains access to the cytosol of Mtb-infected macrophages, where it hydrolyzes the essential coenzyme NAD(+). Expression or injection of a noncatalytic TNT mutant showed no cytotoxicity in macrophages or in zebrafish zygotes, respectively, thus demonstrating that the NAD(+) glycohydrolase activity is required for TNT-induced cell death. To prevent self-poisoning, Mtb produces an immunity factor for TNT (IFT) that binds TNT and inhibits its activity. The crystal structure of the TNT-IFT complex revealed a new NAD(+) glycohydrolase fold of TNT, the founding member of a toxin family widespread in pathogenic microorganisms. PMID:26237511

  9. [Option and evasion of a bachelor's degree programme in nursing evaded students' perception].

    PubMed

    Barlem, Jamila Geri Tomaschewski; Lunardi, Valéria Lerch; Bordignon, Simoní Saraiva; Barlem, Edison Luiz Devos; Lunardi Filho, Wilson Danilo; da Silveira, Rosemary Silva; Zacarias, Caroline Ceolin

    2012-06-01

    Qualitative study, developed in a Federal University in southern Brazil aiming to know the motives for choosing and evading a Bachelor's degree programme in Nursing, in the evaded students 'perception. The data were collected through a questionnaire sent by e-mail to 19 evaded students. The 9 questionnaires that returned were submitted to Qualitative Textual Analysis, and two categories emerged motives to opt for the nursing programme and motives to evade from the nursing programme. The results showed that the option for the programme is associated to personal vocation, perception of Nursing as a profession of care, and its closeness to the health area. Evasion seems to be related to passing the first option of undergraduate programme, ignorance about the profession, financial difficulties, and professional depreciation. We demonstrated that greater emphasis should be put on promoting knowledge about the nursing work, areas of activity and attributions. PMID:23155591

  10. 'Stealth' nanoparticles evade neural immune cells but also evade major brain cell populations: Implications for PEG-based neurotherapeutics.

    PubMed

    Jenkins, Stuart I; Weinberg, Daniel; Al-Shakli, Arwa F; Fernandes, Alinda R; Yiu, Humphrey H P; Telling, Neil D; Roach, Paul; Chari, Divya M

    2016-02-28

    Surface engineering to control cell behavior is of high interest across the chemical engineering, drug delivery and biomaterial communities. Defined chemical strategies are necessary to tailor nanoscale protein interactions/adsorption, enabling control of cell behaviors for development of novel therapeutic strategies. Nanoparticle-based therapies benefit from such strategies but particle targeting to sites of neurological injury remains challenging due to circulatory immune clearance. As a strategy to overcome this barrier, the use of stealth coatings can reduce immune clearance and prolong circulatory times, thereby enhancing therapeutic capacity. Polyethylene glycol (PEG) is the most widely-used stealth coating and facilitates particle accumulation in the brain. However, once within the brain, the mode of handling of PEGylated particles by the resident immune cells of the brain itself (the 'microglia') is unknown. This is a critical question as it is well established that microglia avidly sequester nanoparticles, limiting their bioavailability and posing a major translational barrier. If PEGylation can be proved to promote evasion of microglia, then this information will be of high value in developing tailored nanoparticle-based therapies for neurological applications. Here, we have conducted the first comparative study of uptake of PEGylated particles by all the major (immune and non-immune) brain cell types. We prove for the first time that PEGylated nanoparticles evade major brain cell populations - a phenomenon which will enhance extracellular bioavailability. We demonstrate changes in protein coronas around these particles within biological media, and discuss how surface chemistry presentation may affect this process and subsequent cellular interactions. PMID:26780172

  11. Targeting macrophage activation for the prevention and treatment of S. aureus biofilm infections†

    PubMed Central

    Hanke, Mark L.; Heim, Cortney E.; Angle, Amanda; Sanderson, Sam D.; Kielian, Tammy

    2013-01-01

    Biofilm infections often lead to significant morbidity due to their chronicity and recalcitrance to antibiotics. We have demonstrated that methicillin-resistant Staphylococcus aureus (MRSA) biofilms can evade macrophage antibacterial effector mechanisms by skewing macrophages towards an alternatively activated M2 phenotype. To overcome this immune evasion, we have utilized two complementary approaches. In the first, a proinflammatory milieu was elicited by local administration of classically-activated M1 macrophages and second, by treatment with the C5a receptor (CD88) agonist EP67, which invokes macrophage proinflammatory activity. Early administration of M1-activated macrophages or EP67 significantly attenuated biofilm formation in a mouse model of MRSA catheter-associated infection. Several proinflammatory mediators were significantly elevated in biofilm infected tissues from macrophage- and EP67-treated animals, revealing effective reprogramming of the biofilm environment to a proinflammatory milieu. A requirement for macrophage proinflammatory activity was demonstrated by the fact that transfer of MyD88-deficient macrophages had minimal impact on biofilm growth. Likewise, neutrophil administration had no effect on biofilm formation. Treatment of established biofilm infections with M1-activated macrophages also significantly reduced catheter-associated biofilm burdens compared to antibiotic treatment. Collectively, these results demonstrate that targeting macrophage proinflammatory activity can overcome the local immune inhibitory environment created during biofilm infections and represents a novel therapeutic strategy. PMID:23365077

  12. Suppressive effects of ketamine on macrophage functions

    SciTech Connect

    Chang Yi; Chen, T.-L.; Sheu, J.-R.; Chen, R.-M. . E-mail: rmchen@tmu.edu.tw

    2005-04-01

    Ketamine is an intravenous anesthetic agent. Clinically, induction of anesthesia with ketamine can cause immunosuppression. Macrophages play important roles in host defense. In this study, we attempted to evaluate the effects of ketamine on macrophage functions and its possible mechanism using mouse macrophage-like Raw 264.7 cells as the experimental model. Exposure of macrophages to 10 and 100 {mu}M ketamine, which correspond to 0.1 and 1 times the clinically relevant concentration, for 1, 6, and 24 h had no effect on cell viability or lactate dehydrogenase release. When the administered concentration reached 1000 {mu}M, ketamine caused a release of lactate dehydrogenase and cell death. Ketamine, at 10 and 100 {mu}M, did not affect the chemotactic activity of macrophages. Administration of 1000 {mu}M ketamine in macrophages resulted in a decrease in cell migration. Treatment of macrophages with ketamine reduced phagocytic activities. The oxidative ability of macrophages was suppressed by ketamine. Treatment with lipopolysaccharide induced TNF-{alpha}, IL-1{beta}, and IL-6 mRNA in macrophages. Administration of ketamine alone did not influence TNF-{alpha}, IL-1{beta}, or IL-6 mRNA production. Meanwhile, cotreatment with ketamine and lipopolysaccharide significantly inhibited lipopolysaccharide-induced TNF-{alpha}, IL-1{beta}, and IL-6 mRNA levels. Exposure to ketamine led to a decrease in the mitochondrial membrane potential. However, the activity of mitochondrial complex I NADH dehydrogenase was not affected by ketamine. This study shows that a clinically relevant concentration of ketamine (100 {mu}M) can suppress macrophage function of phagocytosis, its oxidative ability, and inflammatory cytokine production possibly via reduction of the mitochondrial membrane potential instead of direct cellular toxicity.

  13. Macrophage Internal HIV-1 Is Protected from Neutralizing Antibodies

    PubMed Central

    Koppensteiner, Herwig; Banning, Carina; Schneider, Carola; Hohenberg, Heinrich

    2012-01-01

    In macrophages, HIV-1 accumulates in intracellular vesicles designated virus-containing compartments (VCCs). These might play an important role in the constitution of macrophages as viral reservoirs and allow HIV-1 to evade the immune system by sequestration in an internal niche, which is difficult to access from the exterior. However, until now, evidence of whether internal virus accumulations are protected from the host's humoral immune response is still lacking. In order to be able to study the formation and antibody accessibility of VCCs, we generated HIV-1 with green fluorescent protein (GFP)-tagged Gag replicating in primary macrophages. Live-cell observations revealed faint initial cytosolic Gag expression and subsequent large intracellular Gag accumulations which stayed stable over days. Taking advantage of the opportunity to study the accessibility of intracellular VCCs via the cell surface, we demonstrate that macrophage internal HIV-1-containing compartments cannot be targeted by neutralizing antibodies. Furthermore, HIV-1 was efficiently transferred from antibody-treated macrophages to T cells. Three-dimensional reconstruction of electron microscopic slices revealed that Gag accumulations correspond to viral particles within enclosed compartments and convoluted membranes. Thus, although some VCCs were connected to the plasma membrane, the complex membrane architecture of the HIV-1-containing compartment might shield viral particles from neutralizing antibodies. In sum, our study provides evidence that HIV-1 is sequestered into a macrophage internal membranous web, posing an obstacle for the elimination of this viral reservoir. PMID:22205742

  14. [The biological activity of macrophages in health and disease].

    PubMed

    Nazimek, Katarzyna; Bryniarski, Krzysztof

    2012-01-01

    Macrophages are involved in immune response as phagocytes, antigen presenting cells and as effector cells of delayed-type hypersensitivity. Moreover, the activity of macrophages is associated with modulation of many biological processes during the whole life and depends on the actual macrophage phenotype induced under the influence of various microenvironmental stimuli. In pregnancy, placental macrophages induce the development of maternal tolerance to fetal antigens, while fetal macrophages are responsible for proper formation of tissues and organs. Residual macrophages play a very important role in tissue homeostasis, apoptotic cell clearance to prevent autoimmunization and first defense in infections. The inflammatory response of macrophages may be modulated by pathogens. Their suppressive activity is observed in immunologically privileged organs such as testes. In pathologies, macrophages are responsible for tissue damage in a case of nonspecific activation followed by overproduction of proinflammatory factors. Suppression of a specific immune response against tumors is mainly the effect of tumor associated macrophage (TAM) action. On the other hand, presentation of allergens or self-antigens by macrophages and their nonspecific activation by necrotic adipocytes leads to the induction of a chronic inflammatory response and impairment of immunity. Therefore, modulation of macrophage functions may be the key for improvement of therapy of cancer and allergic, autoimmune, metabolic, cardiovascular and Alzheimer's diseases. PMID:22922151

  15. The Role of Decidual Macrophages During Normal and Pathological Pregnancy.

    PubMed

    Ning, Fen; Liu, Huishu; Lash, Gendie E

    2016-03-01

    Macrophages perform many specific functions including host defense, homeostasis, angiogenesis, and tissue development. Macrophages are the second most abundant leukocyte population in the non-pregnant endometrium and pregnant decidua and likely play a central role in the establishment and maintenance of normal pregnancy. Importantly, aberrantly activated uterine macrophages can affect trophoblast function and placental development, which may result in various adverse pregnancy outcomes ranging from pre-eclampsia to fetal growth restriction or demise. Only by fully understanding the roles of macrophage in pregnancy will we be able to develop interventions for the treatment of these various pregnancy complications. This review discusses the general origin and classification of monocytes and macrophages and focuses on the phenotype and functional roles of decidual macrophage at the maternal-fetal interface in normal pregnancy, as well as discussing the potential contribution of the abnormal state of these cells to various aspects of pregnancy pathologies. PMID:26750089

  16. Alveolar macrophage kinetics and function after interruption of canine marrow function

    SciTech Connect

    Springmeyer, S.C.; Altman, L.C.; Kopecky, K.J.; Deeg, H.J.; Storb, R.

    1982-03-01

    To study the kinetics and function of alveolar macrophages after interruption of marrow function, we performed serial bronchoalveolar lavages in dogs. The studies were performed before and after 9.0 to 9.5 Grey total body irradiation and marrow infusion. Monocytes had disappeared from the bloodstream by Day 7 after the irradiation. Alveolar macrophages were significantly decreased at Day 21. At Days 14 and 21 myeloperoxidase-positive alveolar macrophages were also significantly decreased. Beyond Day 30 the number of circulating monocytes, myeloperoxidase-positive and total alveolar macrophages had returned. Sex chromatin stains of alveolar macrophages obtained from a male dog that received female marrow indicated that the repopulating macrophages were of marrow origin. In vitro studies of alveolar macrophage migration and phagocytosis demonstrated increased activities beyond Day 30. These studies suggest that in this model the alveolar macrophage is dependent on the bone marrow for support and that the alveolar macrophage depletion may impair lung defense mechanisms.

  17. HIV-1 Mutation and Recombination Rates Are Different in Macrophages and T-cells

    PubMed Central

    Cromer, Deborah; Schlub, Timothy E.; Smyth, Redmond P.; Grimm, Andrew J.; Chopra, Abha; Mallal, Simon; Davenport, Miles P.; Mak, Johnson

    2016-01-01

    High rates of mutation and recombination help human immunodeficiency virus (HIV) to evade the immune system and develop resistance to antiretroviral therapy. Macrophages and T-cells are the natural target cells of HIV-1 infection. A consensus has not been reached as to whether HIV replication results in differential recombination between primary T-cells and macrophages. Here, we used HIV with silent mutation markers along with next generation sequencing to compare the mutation and the recombination rates of HIV directly in T lymphocytes and macrophages. We observed a more than four-fold higher recombination rate of HIV in macrophages compared to T-cells (p < 0.001) and demonstrated that this difference is not due to different reliance on C-X-C chemokine receptor type 4 (CXCR4) and C-C chemokine receptor type 5 (CCR5) co-receptors between T-cells and macrophages. We also found that the pattern of recombination across the HIV genome (hot and cold spots) remains constant between T-cells and macrophages despite a three-fold increase in the overall recombination rate. This indicates that the difference in rates is a general feature of HIV DNA synthesis during macrophage infection. In contrast to HIV recombination, we found that T-cells have a 30% higher mutation rate than macrophages (p < 0.001) and that the mutational profile is similar between these cell types. Unexpectedly, we found no association between mutation and recombination in macrophages, in contrast to T-cells. Our data highlights some of the fundamental difference of HIV recombination and mutation amongst these two major target cells of infection. Understanding these differences will provide invaluable insights toward HIV evolution and how the virus evades immune surveillance and anti-retroviral therapeutics. PMID:27110814

  18. HIV-1 Mutation and Recombination Rates Are Different in Macrophages and T-cells.

    PubMed

    Cromer, Deborah; Schlub, Timothy E; Smyth, Redmond P; Grimm, Andrew J; Chopra, Abha; Mallal, Simon; Davenport, Miles P; Mak, Johnson

    2016-01-01

    High rates of mutation and recombination help human immunodeficiency virus (HIV) to evade the immune system and develop resistance to antiretroviral therapy. Macrophages and T-cells are the natural target cells of HIV-1 infection. A consensus has not been reached as to whether HIV replication results in differential recombination between primary T-cells and macrophages. Here, we used HIV with silent mutation markers along with next generation sequencing to compare the mutation and the recombination rates of HIV directly in T lymphocytes and macrophages. We observed a more than four-fold higher recombination rate of HIV in macrophages compared to T-cells (p < 0.001) and demonstrated that this difference is not due to different reliance on C-X-C chemokine receptor type 4 (CXCR4) and C-C chemokine receptor type 5 (CCR5) co-receptors between T-cells and macrophages. We also found that the pattern of recombination across the HIV genome (hot and cold spots) remains constant between T-cells and macrophages despite a three-fold increase in the overall recombination rate. This indicates that the difference in rates is a general feature of HIV DNA synthesis during macrophage infection. In contrast to HIV recombination, we found that T-cells have a 30% higher mutation rate than macrophages (p < 0.001) and that the mutational profile is similar between these cell types. Unexpectedly, we found no association between mutation and recombination in macrophages, in contrast to T-cells. Our data highlights some of the fundamental difference of HIV recombination and mutation amongst these two major target cells of infection. Understanding these differences will provide invaluable insights toward HIV evolution and how the virus evades immune surveillance and anti-retroviral therapeutics. PMID:27110814

  19. The Many Alternative Faces of Macrophage Activation.

    PubMed

    Hume, David A

    2015-01-01

    Monocytes and macrophages provide the first line of defense against pathogens. They also initiate acquired immunity by processing and presenting antigens and provide the downstream effector functions. Analysis of large gene expression datasets from multiple cells and tissues reveals sets of genes that are co-regulated with the transcription factors that regulate them. In macrophages, the gene clusters include lineage-specific genes, interferon-responsive genes, early inflammatory genes, and genes required for endocytosis and lysosome function. Macrophages enter tissues and alter their function to deal with a wide range of challenges related to development and organogenesis, tissue injury, malignancy, sterile, or pathogenic inflammatory stimuli. These stimuli alter the gene expression to produce "activated macrophages" that are better equipped to eliminate the cause of their influx and to restore homeostasis. Activation or polarization states of macrophages have been classified as "classical" and "alternative" or M1 and M2. These proposed states of cells are not supported by large-scale transcriptomic data, including macrophage-associated signatures from large cancer tissue datasets, where the supposed markers do not correlate with other. Individual macrophage cells differ markedly from each other, and change their functions in response to doses and combinations of agonists and time. The most studied macrophage activation response is the transcriptional cascade initiated by the TLR4 agonist lipopolysaccharide. This response is reviewed herein. The network topology is conserved across species, but genes within the transcriptional network evolve rapidly and differ between mouse and human. There is also considerable divergence in the sets of target genes between mouse strains, between individuals, and in other species such as pigs. The deluge of complex information related to macrophage activation can be accessed with new analytical tools and new databases that provide

  20. Yersinia pestis Requires Host Rab1b for Survival in Macrophages

    PubMed Central

    Connor, Michael G.; Pulsifer, Amanda R.; Price, Christopher T.; Abu Kwaik, Yousef; Lawrenz, Matthew B.

    2015-01-01

    Yersinia pestis is a facultative intracellular pathogen that causes the disease known as plague. During infection of macrophages Y. pestis actively evades the normal phagosomal maturation pathway to establish a replicative niche within the cell. However, the mechanisms used by Y. pestis to subvert killing by the macrophage are unknown. Host Rab GTPases are central mediators of vesicular trafficking and are commonly targeted by bacterial pathogens to alter phagosome maturation and killing by macrophages. Here we demonstrate for the first time that host Rab1b is required for Y. pestis to effectively evade killing by macrophages. We also show that Rab1b is specifically recruited to the Yersinia containing vacuole (YCV) and that Y. pestis is unable to subvert YCV acidification when Rab1b expression is knocked down in macrophages. Furthermore, Rab1b knockdown also altered the frequency of association between the YCV with the lysosomal marker Lamp1, suggesting that Rab1b recruitment to the YCV directly inhibits phagosome maturation. Finally, we show that Rab1b knockdown also impacts the pH of the Legionella pneumophila containing vacuole, another pathogen that recruits Rab1b to its vacuole. Together these data identify a novel role for Rab1b in the subversion of phagosome maturation by intracellular pathogens and suggest that recruitment of Rab1b to the pathogen containing vacuole may be a conserved mechanism to control vacuole pH. PMID:26495854

  1. Yersinia pestis Requires Host Rab1b for Survival in Macrophages.

    PubMed

    Connor, Michael G; Pulsifer, Amanda R; Price, Christopher T; Abu Kwaik, Yousef; Lawrenz, Matthew B

    2015-10-01

    Yersinia pestis is a facultative intracellular pathogen that causes the disease known as plague. During infection of macrophages Y. pestis actively evades the normal phagosomal maturation pathway to establish a replicative niche within the cell. However, the mechanisms used by Y. pestis to subvert killing by the macrophage are unknown. Host Rab GTPases are central mediators of vesicular trafficking and are commonly targeted by bacterial pathogens to alter phagosome maturation and killing by macrophages. Here we demonstrate for the first time that host Rab1b is required for Y. pestis to effectively evade killing by macrophages. We also show that Rab1b is specifically recruited to the Yersinia containing vacuole (YCV) and that Y. pestis is unable to subvert YCV acidification when Rab1b expression is knocked down in macrophages. Furthermore, Rab1b knockdown also altered the frequency of association between the YCV with the lysosomal marker Lamp1, suggesting that Rab1b recruitment to the YCV directly inhibits phagosome maturation. Finally, we show that Rab1b knockdown also impacts the pH of the Legionella pneumophila containing vacuole, another pathogen that recruits Rab1b to its vacuole. Together these data identify a novel role for Rab1b in the subversion of phagosome maturation by intracellular pathogens and suggest that recruitment of Rab1b to the pathogen containing vacuole may be a conserved mechanism to control vacuole pH. PMID:26495854

  2. Antimicrobial Mechanisms of Macrophages and the Immune Evasion Strategies of Staphylococcus aureus

    PubMed Central

    Flannagan, Ronald S.; Heit, Bryan; Heinrichs, David E.

    2015-01-01

    Habitually professional phagocytes, including macrophages, eradicate microbial invaders from the human body without overt signs of infection. Despite this, there exist select bacteria that are professional pathogens, causing significant morbidity and mortality across the globe and Staphylococcus aureus is no exception. S. aureus is a highly successful pathogen that can infect virtually every tissue that comprises the human body causing a broad spectrum of diseases. The profound pathogenic capacity of S. aureus can be attributed, in part, to its ability to elaborate a profusion of bacterial effectors that circumvent host immunity. Macrophages are important professional phagocytes that contribute to both the innate and adaptive immune response, however from in vitro and in vivo studies, it is evident that they fail to eradicate S. aureus. This review provides an overview of the antimicrobial mechanisms employed by macrophages to combat bacteria and describes the immune evasion strategies and some representative effectors that enable S. aureus to evade macrophage-mediated killing. PMID:26633519

  3. Hepcidin and Host Defense against Infectious Diseases

    PubMed Central

    Michels, Kathryn; Nemeth, Elizabeta; Ganz, Tomas; Mehrad, Borna

    2015-01-01

    Hepcidin is the master regulator of iron homeostasis in vertebrates. The synthesis of hepcidin is induced by systemic iron levels and by inflammatory stimuli. While the role of hepcidin in iron regulation is well established, its contribution to host defense is emerging as complex and multifaceted. In this review, we summarize the literature on the role of hepcidin as a mediator of antimicrobial immunity. Hepcidin induction during infection causes depletion of extracellular iron, which is thought to be a general defense mechanism against many infections by withholding iron from invading pathogens. Conversely, by promoting iron sequestration in macrophages, hepcidin may be detrimental to cellular defense against certain intracellular infections, although critical in vivo studies are needed to confirm this concept. It is not yet clear whether hepcidin exerts any iron-independent effects on host defenses. PMID:26291319

  4. Hepcidin and Host Defense against Infectious Diseases.

    PubMed

    Michels, Kathryn; Nemeth, Elizabeta; Ganz, Tomas; Mehrad, Borna

    2015-08-01

    Hepcidin is the master regulator of iron homeostasis in vertebrates. The synthesis of hepcidin is induced by systemic iron levels and by inflammatory stimuli. While the role of hepcidin in iron regulation is well established, its contribution to host defense is emerging as complex and multifaceted. In this review, we summarize the literature on the role of hepcidin as a mediator of antimicrobial immunity. Hepcidin induction during infection causes depletion of extracellular iron, which is thought to be a general defense mechanism against many infections by withholding iron from invading pathogens. Conversely, by promoting iron sequestration in macrophages, hepcidin may be detrimental to cellular defense against certain intracellular infections, although critical in vivo studies are needed to confirm this concept. It is not yet clear whether hepcidin exerts any iron-independent effects on host defenses. PMID:26291319

  5. Brucella melitensis and Mycobacterium tuberculosis depict overlapping gene expression patterns induced in infected THP-1 macrophages.

    PubMed

    Masoudian, M; Derakhshandeh, A; Ghahramani Seno, M M

    2015-01-01

    Pathogens infecting mammalian cells have developed various strategies to suppress and evade their hosts' defensive mechanisms. In this line, the intracellular bacteria that are able to survive and propagate within their host cells must have developed strategies to avert their host's killing attitude. Studying the interface of host-pathogen confrontation can provide valuable information for defining therapeutic approaches. Brucellosis, caused by the Brucella strains, is a zoonotic bacterial disease that affects thousands of humans and animals around the world inflicting discomfort and huge economic losses. Similar to many other intracellular dwelling bacteria, infections caused by Brucella are difficult to treat, and hence any attempt at identifying new and common therapeutic targets would prove beneficial for the purpose of curing infections caused by the intracellular bacteria. In THP-1 macrophage infected with Brucella melitensis we studied the expression levels of four host's genes, i.e. EMP2, ST8SIA4, HCP5 and FRMD5 known to be involved in pathogenesis of Mycobacterium tuberculosis. Our data showed that at this molecular level, except for FRMD5 that was downregulated, the other three genes were upregulated by B. melitensis. Brucella melitensis and M. tuberculosis go through similar intracellular processes and interestingly two of the investigated genes, i.e. EMP2 and ST4SIA8 were upregulated in THP-1 cell infected with B. melitensis similar to that reported for THP-1 cells infected with M. tuberculosis. At the host-pathogen interaction interface, this study depicts overlapping changes for different bacteria with common survival strategies; a fact that implies designing therapeutic approaches based on common targets may be possible. PMID:27175205

  6. Brucella melitensis and Mycobacterium tuberculosis depict overlapping gene expression patterns induced in infected THP-1 macrophages

    PubMed Central

    Masoudian, M; Derakhshandeh, A; Ghahramani Seno, M. M

    2015-01-01

    Pathogens infecting mammalian cells have developed various strategies to suppress and evade their hosts’ defensive mechanisms. In this line, the intracellular bacteria that are able to survive and propagate within their host cells must have developed strategies to avert their host’s killing attitude. Studying the interface of host-pathogen confrontation can provide valuable information for defining therapeutic approaches. Brucellosis, caused by the Brucella strains, is a zoonotic bacterial disease that affects thousands of humans and animals around the world inflicting discomfort and huge economic losses. Similar to many other intracellular dwelling bacteria, infections caused by Brucella are difficult to treat, and hence any attempt at identifying new and common therapeutic targets would prove beneficial for the purpose of curing infections caused by the intracellular bacteria. In THP-1 macrophage infected with Brucella melitensis we studied the expression levels of four host’s genes, i.e. EMP2, ST8SIA4, HCP5 and FRMD5 known to be involved in pathogenesis of Mycobacterium tuberculosis. Our data showed that at this molecular level, except for FRMD5 that was downregulated, the other three genes were upregulated by B. melitensis. Brucella melitensis and M. tuberculosis go through similar intracellular processes and interestingly two of the investigated genes, i.e. EMP2 and ST4SIA8 were upregulated in THP-1 cell infected with B. melitensis similar to that reported for THP-1 cells infected with M. tuberculosis. At the host-pathogen interaction interface, this study depicts overlapping changes for different bacteria with common survival strategies; a fact that implies designing therapeutic approaches based on common targets may be possible. PMID:27175205

  7. Macrophage phenotypes in atherosclerosis.

    PubMed

    Colin, Sophie; Chinetti-Gbaguidi, Giulia; Staels, Bart

    2014-11-01

    Initiation and progression of atherosclerosis depend on local inflammation and accumulation of lipids in the vascular wall. Although many cells are involved in the development and progression of atherosclerosis, macrophages are fundamental contributors. For nearly a decade, the phenotypic heterogeneity and plasticity of macrophages has been studied. In atherosclerotic lesions, macrophages are submitted to a large variety of micro-environmental signals, such as oxidized lipids and cytokines, which influence the phenotypic polarization and activation of macrophages resulting in a dynamic plasticity. The macrophage phenotype spectrum is characterized, at the extremes, by the classical M1 macrophages induced by T-helper 1 (Th-1) cytokines and by the alternative M2 macrophages induced by Th-2 cytokines. M2 macrophages can be further classified into M2a, M2b, M2c, and M2d subtypes. More recently, additional plaque-specific macrophage phenotypes have been identified, termed as Mox, Mhem, and M4. Understanding the mechanisms and functional consequences of the phenotypic heterogeneity of macrophages will contribute to determine their potential role in lesion development and plaque stability. Furthermore, research on macrophage plasticity could lead to novel therapeutic approaches to counteract cardiovascular diseases such as atherosclerosis. The present review summarizes our current knowledge on macrophage subsets in atherosclerotic plaques and mechanism behind the modulation of the macrophage phenotype. PMID:25319333

  8. Smuggling across the border: how arthropod-borne pathogens evade and exploit the host defense system of the skin.

    PubMed

    Bernard, Quentin; Jaulhac, Benoit; Boulanger, Nathalie

    2014-05-01

    The skin is a critical barrier between hosts and pathogens in arthropod-borne diseases. It harbors many resident cells and specific immune cells to arrest or limit infections by secreting inflammatory molecules or by directly killing pathogens. However, some pathogens are able to use specific skin cells and arthropod saliva for their initial development, to hide from the host immune system, and to establish persistent infection in the vertebrate host. A better understanding of the initial mechanisms taking place in the skin should allow the development of new strategies to fight these vector-borne pathogens that are spread worldwide and are of major medical importance. PMID:24552683

  9. The Many Alternative Faces of Macrophage Activation

    PubMed Central

    Hume, David A.

    2015-01-01

    Monocytes and macrophages provide the first line of defense against pathogens. They also initiate acquired immunity by processing and presenting antigens and provide the downstream effector functions. Analysis of large gene expression datasets from multiple cells and tissues reveals sets of genes that are co-regulated with the transcription factors that regulate them. In macrophages, the gene clusters include lineage-specific genes, interferon-responsive genes, early inflammatory genes, and genes required for endocytosis and lysosome function. Macrophages enter tissues and alter their function to deal with a wide range of challenges related to development and organogenesis, tissue injury, malignancy, sterile, or pathogenic inflammatory stimuli. These stimuli alter the gene expression to produce “activated macrophages” that are better equipped to eliminate the cause of their influx and to restore homeostasis. Activation or polarization states of macrophages have been classified as “classical” and “alternative” or M1 and M2. These proposed states of cells are not supported by large-scale transcriptomic data, including macrophage-associated signatures from large cancer tissue datasets, where the supposed markers do not correlate with other. Individual macrophage cells differ markedly from each other, and change their functions in response to doses and combinations of agonists and time. The most studied macrophage activation response is the transcriptional cascade initiated by the TLR4 agonist lipopolysaccharide. This response is reviewed herein. The network topology is conserved across species, but genes within the transcriptional network evolve rapidly and differ between mouse and human. There is also considerable divergence in the sets of target genes between mouse strains, between individuals, and in other species such as pigs. The deluge of complex information related to macrophage activation can be accessed with new analytical tools and new databases

  10. Surface modification of nanoparticles enables selective evasion of phagocytic clearance by distinct macrophage phenotypes.

    PubMed

    Qie, Yaqing; Yuan, Hengfeng; von Roemeling, Christina A; Chen, Yuanxin; Liu, Xiujie; Shih, Kevin D; Knight, Joshua A; Tun, Han W; Wharen, Robert E; Jiang, Wen; Kim, Betty Y S

    2016-01-01

    Nanomedicine is a burgeoning industry but an understanding of the interaction of nanomaterials with the immune system is critical for clinical translation. Macrophages play a fundamental role in the immune system by engulfing foreign particulates such as nanoparticles. When activated, macrophages form distinct phenotypic populations with unique immune functions, however the mechanism by which these polarized macrophages react to nanoparticles is unclear. Furthermore, strategies to selectively evade activated macrophage subpopulations are lacking. Here we demonstrate that stimulated macrophages possess higher phagocytic activities and that classically activated (M1) macrophages exhibit greater phagocytic capacity than alternatively activated (M2) macrophages. We show that modification of nanoparticles with polyethylene-glycol results in decreased clearance by all macrophage phenotypes, but importantly, coating nanoparticles with CD47 preferentially lowers phagocytic activity by the M1 phenotype. These results suggest that bio-inspired nanoparticle surface design may enable evasion of specific components of the immune system and provide a rational approach for developing immune tolerant nanomedicines. PMID:27197045

  11. Surface modification of nanoparticles enables selective evasion of phagocytic clearance by distinct macrophage phenotypes

    PubMed Central

    Qie, Yaqing; Yuan, Hengfeng; von Roemeling, Christina A.; Chen, Yuanxin; Liu, Xiujie; Shih, Kevin D.; Knight, Joshua A.; Tun, Han W.; Wharen, Robert E.; Jiang, Wen; Kim, Betty Y.S.

    2016-01-01

    Nanomedicine is a burgeoning industry but an understanding of the interaction of nanomaterials with the immune system is critical for clinical translation. Macrophages play a fundamental role in the immune system by engulfing foreign particulates such as nanoparticles. When activated, macrophages form distinct phenotypic populations with unique immune functions, however the mechanism by which these polarized macrophages react to nanoparticles is unclear. Furthermore, strategies to selectively evade activated macrophage subpopulations are lacking. Here we demonstrate that stimulated macrophages possess higher phagocytic activities and that classically activated (M1) macrophages exhibit greater phagocytic capacity than alternatively activated (M2) macrophages. We show that modification of nanoparticles with polyethylene-glycol results in decreased clearance by all macrophage phenotypes, but importantly, coating nanoparticles with CD47 preferentially lowers phagocytic activity by the M1 phenotype. These results suggest that bio-inspired nanoparticle surface design may enable evasion of specific components of the immune system and provide a rational approach for developing immune tolerant nanomedicines. PMID:27197045

  12. Cytosolic Replication of Group A Streptococcus in Human Macrophages

    PubMed Central

    O’Neill, Alan M.; Thurston, Teresa L. M.

    2016-01-01

    ABSTRACT As key components of innate immune defense, macrophages are essential in controlling bacterial pathogens, including group A Streptococcus (GAS). Despite this, only a limited number of studies have analyzed the recovery of GAS from within human neutrophils and macrophages. Here, we determined the intracellular fate of GAS in human macrophages by using several quantitative approaches. In both U937 and primary human macrophages, the appearance over time of long GAS chains revealed that despite GAS-mediated cytotoxicity, replication occurred in viable, propidium iodide-negative macrophages. Whereas the major virulence factor M1 did not contribute to bacterial growth, a GAS mutant strain deficient in streptolysin O (SLO) was impaired for intracellular replication. SLO promoted bacterial escape from the GAS-containing vacuole (GCV) into the macrophage cytosol. Up to half of the cytosolic GAS colocalized with ubiquitin and p62, suggesting that the bacteria were targeted by the autophagy machinery. Despite this, live imaging of U937 macrophages revealed proficient replication of GAS after GCV rupture, indicating that escape from the GCV is important for growth of GAS in macrophages. Our results reveal that GAS can replicate within viable human macrophages, with SLO promoting GCV escape and cytosolic growth, despite the recruitment of autophagy receptors to bacteria. PMID:27073088

  13. Autophagy as a macrophage response to bacterial infection.

    PubMed

    Gong, Lan; Devenish, Rodney J; Prescott, Mark

    2012-09-01

    The macrophage is a key component of host defense mechanisms against pathogens. In addition to the phagocytosis of bacteria and secretion of proinflammatory mediators by macrophages, autophagy, a process involved in turnover of cellular material, is a recently identified component of the immune response to bacterial infection. Despite the bactericidal effect of autophagy, some species of intracellular bacteria are able to survive by using one or more strategies to avoid host autophagic attack. Here, we review the latest findings on the interactions between bacteria and autophagy in macrophages. PMID:22815102

  14. Values as Defenses

    ERIC Educational Resources Information Center

    Hultman, Kenneth E.

    1976-01-01

    The author outlines a cognitive approach for explaining how and why people use values as defenses. He examines the relationship between defensive values and irrational beliefs, suggests a number of criteria for diagnosing the presence of defensive values, and proposes some strategies for dealing with defensive values in counseling. (Author)

  15. [Drug Dependence and Cytotoxicity of Law-evading Drugs: Their Identities Explored from Basic Research].

    PubMed

    Funada, Masahiko

    2016-01-01

      Cases of people experiencing disturbed consciousness or dyspnea, causing traffic accidents, or requiring ambulance transport to hospital due to abuse of law-evading chemical substances have become a serious social problem in Japan. Most law-evading herbal products are marketed as incense or herbs and consist of finely chopped, dry vegetative matter mixed with chemical substances (drugs). Analysis of the chemical substances in these herbal products has demonstrated that they contain synthetic cannabinoids. Because there are many cannabinoid compounds, even if a particular drug is regulated, similar compounds that differ only slightly in structure may be added in their place. Therefore a cat-and-mouse game exists between regulations on chemical substances and their propagation. This paper summarizes the pharmacological actions and dangers of chemical substances contained in law-evading herbal products by focusing on synthetic cannabinoids, as a group of chemical substances contained in these products. Furthermore, comprehensive designations of synthetic cannabinoids have been introduced as a new method of regulation that emphasizes the similarity of chemical structures; this paper also outlines the comprehensive designations. We established a psychic-dependence liability and cytotoxicity screening system for synthetic cannabinoids using animals (behavioral analysis in vivo) and cell cultures (cytotoxicity analysis in vitro). With our drug-screening system, we were able rapidly to evaluate and quantify psychic-dependence liabilities and cytotoxicity of synthetic cannabinoids contained in law-evading herbal products. These scientific data using our screening system contributed to the establishment of legislation for comprehensive designations of synthetic cannabinoids. PMID:26725670

  16. The Elicitin-Like Glycoprotein, ELI025, Is Secreted by the Pathogenic Oomycete Pythium insidiosum and Evades Host Antibody Responses

    PubMed Central

    Lerksuthirat, Tassanee; Lohnoo, Tassanee; Inkomlue, Ruchuros; Rujirawat, Thidarat; Yingyong, Wanta; Khositnithikul, Rommanee; Phaonakrop, Narumon; Roytrakul, Sittiruk; Sullivan, Thomas D.; Krajaejun, Theerapong

    2015-01-01

    Pythium insidiosum is a unique oomycete that can infect humans and animals. Patients with a P. insidiosum infection (pythiosis) have high rates of morbidity and mortality. The pathogen resists conventional antifungal drugs. Information on the biology and pathogenesis of P. insidiosum is limited. Many pathogens secrete proteins, known as effectors, which can affect the host response and promote the infection process. Elicitins are secretory proteins and are found only in the oomycetes, primarily in Phytophthora and Pythium species. In plant-pathogenic oomycetes, elicitins function as pathogen-associated molecular pattern molecules, sterol carriers, and plant defense stimulators. Recently, we reported a number of elicitin-encoding genes from the P. insidiosum transcriptome. The function of elicitins during human infections is unknown. One of the P. insidiosum elicitin-encoding genes, ELI025, is highly expressed and up-regulated at body temperature. This study aims to characterize the biochemical, immunological, and genetic properties of the elicitin protein, ELI025. A 12.4-kDa recombinant ELI025 protein (rELI025) was expressed in Escherichia coli. Rabbit anti-rELI025 antibodies reacted strongly with the native ELI025 in P. insidiosum’s culture medium. The detected ELI025 had two isoforms: glycosylated and non-glycosylated. ELI025 was not immunoreactive with sera from pythiosis patients. The region near the transcriptional start site of ELI025 contained conserved oomycete core promoter elements. In conclusion, ELI025 is a small, abundant, secreted glycoprotein that evades host antibody responses. ELI025 is a promising candidate for development of diagnostic and therapeutic targets for pythiosis. PMID:25793767

  17. The elicitin-like glycoprotein, ELI025, is secreted by the pathogenic oomycete Pythium insidiosum and evades host antibody responses.

    PubMed

    Lerksuthirat, Tassanee; Lohnoo, Tassanee; Inkomlue, Ruchuros; Rujirawat, Thidarat; Yingyong, Wanta; Khositnithikul, Rommanee; Phaonakrop, Narumon; Roytrakul, Sittiruk; Sullivan, Thomas D; Krajaejun, Theerapong

    2015-01-01

    Pythium insidiosum is a unique oomycete that can infect humans and animals. Patients with a P. insidiosum infection (pythiosis) have high rates of morbidity and mortality. The pathogen resists conventional antifungal drugs. Information on the biology and pathogenesis of P. insidiosum is limited. Many pathogens secrete proteins, known as effectors, which can affect the host response and promote the infection process. Elicitins are secretory proteins and are found only in the oomycetes, primarily in Phytophthora and Pythium species. In plant-pathogenic oomycetes, elicitins function as pathogen-associated molecular pattern molecules, sterol carriers, and plant defense stimulators. Recently, we reported a number of elicitin-encoding genes from the P. insidiosum transcriptome. The function of elicitins during human infections is unknown. One of the P. insidiosum elicitin-encoding genes, ELI025, is highly expressed and up-regulated at body temperature. This study aims to characterize the biochemical, immunological, and genetic properties of the elicitin protein, ELI025. A 12.4-kDa recombinant ELI025 protein (rELI025) was expressed in Escherichia coli. Rabbit anti-rELI025 antibodies reacted strongly with the native ELI025 in P. insidiosum's culture medium. The detected ELI025 had two isoforms: glycosylated and non-glycosylated. ELI025 was not immunoreactive with sera from pythiosis patients. The region near the transcriptional start site of ELI025 contained conserved oomycete core promoter elements. In conclusion, ELI025 is a small, abundant, secreted glycoprotein that evades host antibody responses. ELI025 is a promising candidate for development of diagnostic and therapeutic targets for pythiosis. PMID:25793767

  18. Macrophages: sentinels and regulators of the immune system.

    PubMed

    Franken, Lars; Schiwon, Marzena; Kurts, Christian

    2016-04-01

    The important role of macrophages in host defense against a variety of pathogens has long been recognized and has been documented and reviewed in numerous publications. Recently, it has become clear that tissue macrophages are not entirely derived from monocytes, as has been assumed for a long time, but rather show an ontogenetic dichotomy in most tissues: while part of the tissue macrophages are derived from monocytes, a major subset is prenatally seeded from the yolk sac. The latter subset shows a remarkable longevity and is maintained by self-renewal in the adult animal. This paradigm shift poses interesting questions: are these two macrophage subsets functionally equivalent cells that are recruited into the tissue at different development stages, or are both macrophage subsets discrete cell types with distinct functions, which have to exist side by side? Is the functional specialization that can be observed in most macrophages due to their lineage or due to their anatomical niche? This review will give an overview about what we know of macrophage ontogeny and will discuss the influence of the macrophage lineage and location on their functional specialization. PMID:26880038

  19. It is all about fluidity: Fatty acids and macrophage phagocytosis.

    PubMed

    Schumann, Julia

    2016-08-15

    Phagocytosis is an early and fundamental step for the effective clearance of disease causing agents. The ability to engulf and kill pathogens is considered as a major effector function of macrophages. In their phagocytic role macrophages are part of the first line of innate immune defense. A number of studies investigating fatty acid effects on macrophage phagocytosis have been conducted over many years. In vitro-data consistently report that alterations in macrophage membrane fatty acid composition are linked to an altered phagocytic capacity, i.e. an increase in membrane unsaturated fatty acid content is associated with an increase in engulfment and killing rate. The mode of action of fatty acids seems to be the modulation of the physical nature of the macrophage plasma membrane. It appears that the saturated-to-unsaturated fatty acid ratio of macrophage membrane phospholipids is of importance in determining macrophage phagocytic capacity. Available in vivo-data are less clear. At present, there is a lack of systematic studies elucidating key factors such as fatty acid efficacy, effective dose or dosing intervals. Without this knowledge the targeted modulation of macrophage phagocytosis in vivo by fatty acids is still a distant possibility. PMID:25987422

  20. Macrophage Pro-Resolving Mediators—the When and Where

    PubMed Central

    DALLI, JESMOND; SERHAN, CHARLES

    2016-01-01

    Macrophages and neutrophils orchestrate acute inflammation and host defense as well as the resolution phase and return to homeostasis. In this article, we review the contribution of macrophages to local lipid mediator (LM) levels and the regulation of macrophage LM profiles by neutrophils and neutrophil-derived microparticles. We carried out LM metabololipidomics profiling distinct phagocytes: neutrophils (PMN), apoptotic PMN, and macrophages. Efferocytosis increased specialized proresolving mediator (SPM) biosynthesis, including Resolvin D1 (RvD1), RvD2, and RvE2, which were further elevated by PMN microparticles. Using deuterium-labeled precursors (d8-arachidonic acid, d5-eicosapentaenoic acid, and d5-docosahexaenoic acid), apoptotic PMN and microparticles contributed to SPM biosynthesis during efferocytosis. Assessment of macrophage LM profiles in M2 macrophages demonstrated higher SPM levels in this macrophage subset, including maresin 1 (MaR1), and lower amounts of leukotriene B4 and prostaglandins than M1. Apoptotic PMN uptake by both macrophage subtypes led to modulation of their LM profiles. Leukotriene B4 was down-regulated in M2 whereas SPM including lipoxin A4 were increased. Conversely, uptake of apoptotic PMN by M2 macrophages reduced (~ 25%) overall LM. MaR1 displays potent tissue regenerative and anti-nociceptive actions in addition to its pro-resolving and anti-inflammatory actions. In addition the MaR1 biosynthetic intermediate 13S,14S-epoxy-Maresin is also bioactive, inhibiting LTB4 biosynthesis and switching macrophage phenotypes from M1 to M2. Together, these results establish LM signature profiles of human phagocytes and related subpopulations. They demonstrate microparticle regulation of specific macrophage endogenous LM during defined stages of acute inflammation and their dynamic changes in human primary phagocytes. PMID:27337457

  1. Dendritic cells and macrophages in the genitourinary tract

    PubMed Central

    Iijima, N; Thompson, JM; Iwasaki, A

    2009-01-01

    Dendritic cells (DCs) and macrophages are antigen-presenting cells (APCs) that are important in innate immune defense as well as in the generation and regulation of adaptive immunity against a wide array of pathogens. The genitourinary (GU) tract, which serves an important reproductive function, is constantly exposed to numerous agents of sexually transmitted infections (STIs). To combat these STIs, several subsets of DCs and macrophages are strategically localized within the GU tract. In the female genital mucosa, recruitment and function of these APCs are uniquely governed by sex hormones. This review summarizes the latest advances in our understanding of DCs and macrophages in the GU tract with respect to their subsets, lineage, and function. In addition, we discuss the divergent roles of these cells in immune defense against STIs as well as in maternal tolerance to the fetus. PMID:19079212

  2. Pulmonary and thoracic macrophage subpopulations and clearance of particles from the lung.

    PubMed Central

    Lehnert, B E

    1992-01-01

    Pulmonary macrophages consist of several subpopulations that can be defined by their anatomical locations as well as by other criteria. In addition to the well-known alveolar macrophages that reside on the alveolar surface, pulmonary macrophages also occur in the conducting airways, in various pulmonary interstitial regions, and, in some mammalian species, in the lung's intravascular compartment. Other thoracic macrophages of relevance to pulmonary defense and some lung disease processes are the pleural macrophages resident in the pleural space and macrophages present in regional lymph nodes that receive lymphatic drainage from the lung. Of the above subpopulations of pulmonary and thoracic macrophages, the alveolar macrophages have received the most experimental attention in the context of the pulmonary clearance and retention of deposited particles. Accordingly, less information is currently available regarding the roles other pulmonary and thoracic populations of macrophages may play in the removal of particles from the lower respiratory tract and associated tissue compartments. This report provides an overview of the various subpopulations of pulmonary and thoracic macrophages, as defined by their anatomical locations. The known and postulated roles of macrophages in the pulmonary clearance and retention of particles are reviewed, with particular emphasis on macrophage-associated processes involved in the pulmonary clearance of relatively insoluble particles. Images FIGURE 1. FIGURE 2. FIGURE 3. FIGURE 5. FIGURE 8. FIGURE 12. FIGURE 14. FIGURE 15. FIGURE 16. FIGURE 17. FIGURE 18. FIGURE 19. A FIGURE 19. B FIGURE 21. FIGURE 22. PMID:1396454

  3. Enhanced resistance against Listeria monocytogenes at an early phase of primary infection in pregnant mice: activation of macrophages during pregnancy.

    PubMed Central

    Watanabe, Y; Mitsuyama, M; Sano, M; Nakano, H; Nomoto, K

    1986-01-01

    We investigated the pregnancy-induced changes in macrophage activity which are important in the expression of host defense against infections. Several macrophage functions were examined by using Listeria monocytogenes. In pregnant mice, prolonged survival and enhanced in vivo elimination of bacteria were observed in the early phase of primary infection. Functions of peritoneal macrophages, including in vitro phagocytosis intracellular killing, glucose consumption, generation of superoxide anion, and intracellular beta-glucuronidase activity were shown to be enhanced in pregnant mice. These findings indicate that pregnancy enhances macrophage functions qualitatively. Possible mechanisms for this enhancement and the significance of macrophage activation for pregnant hosts are discussed. PMID:3011673

  4. Effects of immunopotentiating agents on alveolar macrophage properties.

    PubMed

    Charley, B

    1986-01-01

    Infectious respiratory diseases in man and in domestic animals are characterized by the presence of a large number of different microorganisms: viruses, bacterias, mycoplasmas. It is therefore necessary to stimulate non-specific defense mechanisms in the lung and especially alveolar macrophages (AM). These cells, located in the alveolar air-spaces, play a major role in the lung clearance mechanisms and exert antibacterial, antiviral and antitumoral activities. Activation of alveolar macrophages was studied in vitro with lipopolysaccharide (LPS), lymphokines or mycobacterial derivatives (MDP). Rodent alveolar macrophages were rendered cytotoxic by in vitro exposure to LPS, free MDP or liposome-encapsulated MDP derivatives. In vivo, intravenously administered liposomes containing lipophilic MDP derivatives induced cytotoxic alveolar macrophages and protected mice against the development of pulmonary metastases. PMID:3539492

  5. Macrophage Autophagy in Atherosclerosis

    PubMed Central

    Maiuri, Maria Chiara; Grassia, Gianluca; Platt, Andrew M.; Carnuccio, Rosa; Ialenti, Armando; Maffia, Pasquale

    2013-01-01

    Macrophages play crucial roles in atherosclerotic immune responses. Recent investigation into macrophage autophagy (AP) in atherosclerosis has demonstrated a novel pathway through which these cells contribute to vascular inflammation. AP is a cellular catabolic process involving the delivery of cytoplasmic contents to the lysosomal machinery for ultimate degradation and recycling. Basal levels of macrophage AP play an essential role in atheroprotection during early atherosclerosis. However, AP becomes dysfunctional in the more advanced stages of the pathology and its deficiency promotes vascular inflammation, oxidative stress, and plaque necrosis. In this paper, we will discuss the role of macrophages and AP in atherosclerosis and the emerging evidence demonstrating the contribution of macrophage AP to vascular pathology. Finally, we will discuss how AP could be targeted for therapeutic utility. PMID:23401644

  6. Radiological Defense. Textbook.

    ERIC Educational Resources Information Center

    Defense Civil Preparedness Agency (DOD), Washington, DC.

    This textbook has been prepared under the direction of the Defense Civil Preparedness Agency (DCPA) Staff College for use as a student reference manual in radiological defense (RADEF) courses. It provides much of the basic technical information necessary for a proper understanding of radiological defense and summarizes RADEF planning and expected…

  7. [The Characteristics of Law-evading Drug Users and Effective Approaches].

    PubMed

    Kondo, Ayumi

    2016-01-01

      The increasing number of law-evading drug users in Japan is becoming a serious social problem. Previous studies have shown that law-evading drug users are younger, more educated, and less antisocial than methamphetamine users. They also tend to have some type of psychiatric disorder before starting drug use; therefore one of the reasons that they start using drugs may be to alleviate certain psychiatric symptoms. Furthermore, if drug users are successful in avoiding arrest, they often lack the motivation to stop, which makes treatment difficult. Therapists are required to be non-confrontational, to keep pace with their patients, and to take their patients' other existing disorders into account. Recently, the Matrix Model has shown promise as a new treatment strategy for drug abusers in Japan. The Matrix Model, which was originally developed in response to the 1980s cocaine epidemic in the USA, is an intensive outpatient treatment approach for drug abuse and dependence. The Matrix Model integrates cognitive-behavioral therapy, contingency management, motivational interviewing, 12-step facilitation, family involvement, and so on, with a directive, non-confrontational approach, and this style of therapy seems to fit with law-evading drug users. A Matrix Model-based treatment program was first established in Japan in 2006. The aim of this report is to introduce and assess the benefits of the TAMA Mental Health and Welfare Center Relapse Prevention Program, a Matrix Model-based treatment program established at the Tama Mental Health and Welfare Center in 2007. PMID:26725673

  8. INHALABLE PARTICLES AND PULMONARY HOST DEFENSE: 'IN VIVO' AND 'IN VITRO' EFFECTS OF AMBIENT AIR AND COMBUSTION PARTICLES

    EPA Science Inventory

    The ability of particulate air pollutants (and possible constituents) to alter pulmonary host defenses was examined using an in vitro alveolar macrophage cytotoxicity assay and an in vivo bacterial infectivity screening test which employed intratracheal injection of the particles...

  9. How Can Plant DNA Viruses Evade siRNA-Directed DNA Methylation and Silencing?

    PubMed Central

    Pooggin, Mikhail M.

    2013-01-01

    Plants infected with DNA viruses produce massive quantities of virus-derived, 24-nucleotide short interfering RNAs (siRNAs), which can potentially direct viral DNA methylation and transcriptional silencing. However, growing evidence indicates that the circular double-stranded DNA accumulating in the nucleus for Pol II-mediated transcription of viral genes is not methylated. Hence, DNA viruses most likely evade or suppress RNA-directed DNA methylation. This review describes the specialized mechanisms of replication and silencing evasion evolved by geminiviruses and pararetoviruses, which rescue viral DNA from repressive methylation and interfere with transcriptional and post-transcriptional silencing of viral genes. PMID:23887650

  10. A Possible Mechanism for Evading Temperature Quantum Decoherence in Living Matter by Feshbach Resonance

    PubMed Central

    Poccia, Nicola; Ricci, Alessandro; Innocenti, Davide; Bianconi, Antonio

    2009-01-01

    A new possible scenario for the origin of the molecular collective behaviour associated with the emergence of living matter is presented. We propose that the transition from a non-living to a living cell could be mapped to a quantum transition to a coherent entanglement of condensates, like in a multigap BCS superconductor. Here the decoherence-evading qualities at high temperature are based on the Feshbach resonance that has been recently proposed as the driving mechanism for high Tc superconductors. Finally we discuss how the proximity to a particular critical point is relevant to the emergence of coherence in the living cell. PMID:19564941

  11. Evading surface and detector frequency noise in harmonic oscillator measurements of force gradients

    PubMed Central

    Moore, Eric W.; Lee, SangGap; Hickman, Steven A.; Harrell, Lee E.; Marohn, John A.

    2010-01-01

    We introduce and demonstrate a method of measuring small force gradients acting on a harmonic oscillator in which the force-gradient signal of interest is used to parametrically up-convert a forced oscillation below resonance into an amplitude signal at the oscillator’s resonance frequency. The approach, which we demonstrate in a mechanically detected electron spin resonance experiment, allows the force-gradient signal to evade detector frequency noise by converting a slowly modulated frequency signal into an amplitude signal. PMID:20733934

  12. Alternative activation of macrophages and pulmonary fibrosis are modulated by scavenger receptor, macrophage receptor with collagenous structure.

    PubMed

    Murthy, Shubha; Larson-Casey, Jennifer L; Ryan, Alan J; He, Chao; Kobzik, Lester; Carter, A Brent

    2015-08-01

    Alternative activation of alveolar macrophages is linked to fibrosis following exposure to asbestos. The scavenger receptor, macrophage receptor with collagenous structure (MARCO), provides innate immune defense against inhaled particles and pathogens; however, a receptor for asbestos has not been identified. We hypothesized that MARCO acts as an initial signaling receptor for asbestos, polarizes macrophages to a profibrotic M2 phenotype, and is required for the development of asbestos-induced fibrosis. Compared with normal subjects, alveolar macrophages isolated from patients with asbestosis express higher amounts of MARCO and have greater profibrotic polarization. Arginase 1 (40-fold) and IL-10 (265-fold) were higher in patients. In vivo, the genetic deletion of MARCO attenuated the profibrotic environment and pulmonary fibrosis in mice exposed to chrysotile. Moreover, alveolar macrophages from MARCO(-/-) mice polarize to an M1 phenotype, whereas wild-type mice have higher Ym1 (>3.0-fold) and nearly 7-fold more active TGF-β1 in bronchoalveolar lavage (BAL) fluid (BALF). Arg(432) and Arg(434) in domain V of MARCO are required for the polarization of macrophages to a profibrotic phenotype as mutation of these residues reduced FIZZ1 expression (17-fold) compared with cells expressing MARCO. These observations demonstrate that a macrophage membrane protein regulates the fibrotic response to lung injury and suggest a novel target for therapeutic intervention. PMID:25953850

  13. Glutamine Modulates Macrophage Lipotoxicity

    PubMed Central

    He, Li; Weber, Kassandra J.; Schilling, Joel D.

    2016-01-01

    Obesity and diabetes are associated with excessive inflammation and impaired wound healing. Increasing evidence suggests that macrophage dysfunction is responsible for these inflammatory defects. In the setting of excess nutrients, particularly dietary saturated fatty acids (SFAs), activated macrophages develop lysosome dysfunction, which triggers activation of the NLRP3 inflammasome and cell death. The molecular pathways that connect lipid stress to lysosome pathology are not well understood, but may represent a viable target for therapy. Glutamine uptake is increased in activated macrophages leading us to hypothesize that in the context of excess lipids glutamine metabolism could overwhelm the mitochondria and promote the accumulation of toxic metabolites. To investigate this question we assessed macrophage lipotoxicity in the absence of glutamine using LPS-activated peritoneal macrophages exposed to the SFA palmitate. We found that glutamine deficiency reduced lipid induced lysosome dysfunction, inflammasome activation, and cell death. Under glutamine deficient conditions mTOR activation was decreased and autophagy was enhanced; however, autophagy was dispensable for the rescue phenotype. Rather, glutamine deficiency prevented the suppressive effect of the SFA palmitate on mitochondrial respiration and this phenotype was associated with protection from macrophage cell death. Together, these findings reveal that crosstalk between activation-induced metabolic reprogramming and the nutrient microenvironment can dramatically alter macrophage responses to inflammatory stimuli. PMID:27077881

  14. M2 polarization enhances silica nanoparticle uptake by macrophages.

    PubMed

    Hoppstädter, Jessica; Seif, Michelle; Dembek, Anna; Cavelius, Christian; Huwer, Hanno; Kraegeloh, Annette; Kiemer, Alexandra K

    2015-01-01

    While silica nanoparticles have enabled numerous industrial and medical applications, their toxicological safety requires further evaluation. Macrophages are the major cell population responsible for nanoparticle clearance in vivo. The prevailing macrophage phenotype largely depends on the local immune status of the host. Whereas M1-polarized macrophages are considered as pro-inflammatory macrophages involved in host defense, M2 macrophages exhibit anti-inflammatory and wound-healing properties, but also promote tumor growth. We employed different models of M1 and M2 polarization: granulocyte-macrophage colony-stimulating factor/lipopolysaccharide (LPS)/interferon (IFN)-γ was used to generate primary human M1 cells and macrophage colony-stimulating factor (M-CSF)/interleukin (IL)-10 to differentiate M2 monocyte-derived macrophages (MDM). PMA-differentiated THP-1 cells were polarized towards an M1 type by LPS/IFN-γ and towards M2 by IL-10. Uptake of fluorescent silica nanoparticles (Ø26 and 41 nm) and microparticles (Ø1.75 μm) was quantified. At the concentration used (50 μg/ml), silica nanoparticles did not influence cell viability as assessed by MTT assay. Nanoparticle uptake was enhanced in M2-polarized primary human MDM compared with M1 cells, as shown by flow cytometric and microscopic approaches. In contrast, the uptake of microparticles did not differ between M1 and M2 phenotypes. M2 polarization was also associated with increased nanoparticle uptake in the macrophage-like THP-1 cell line. In accordance, in vivo polarized M2-like primary human tumor-associated macrophages obtained from lung tumors took up more nanoparticles than M1-like alveolar macrophages isolated from the surrounding lung tissue. In summary, our data indicate that the M2 polarization of macrophages promotes nanoparticle internalization. Therefore, the phenotypical differences between macrophage subsets should be taken into consideration in future investigations on nanosafety, but

  15. M2 polarization enhances silica nanoparticle uptake by macrophages

    PubMed Central

    Hoppstädter, Jessica; Seif, Michelle; Dembek, Anna; Cavelius, Christian; Huwer, Hanno; Kraegeloh, Annette; Kiemer, Alexandra K.

    2015-01-01

    While silica nanoparticles have enabled numerous industrial and medical applications, their toxicological safety requires further evaluation. Macrophages are the major cell population responsible for nanoparticle clearance in vivo. The prevailing macrophage phenotype largely depends on the local immune status of the host. Whereas M1-polarized macrophages are considered as pro-inflammatory macrophages involved in host defense, M2 macrophages exhibit anti-inflammatory and wound-healing properties, but also promote tumor growth. We employed different models of M1 and M2 polarization: granulocyte-macrophage colony-stimulating factor/lipopolysaccharide (LPS)/interferon (IFN)-γ was used to generate primary human M1 cells and macrophage colony-stimulating factor (M-CSF)/interleukin (IL)-10 to differentiate M2 monocyte-derived macrophages (MDM). PMA-differentiated THP-1 cells were polarized towards an M1 type by LPS/IFN-γ and towards M2 by IL-10. Uptake of fluorescent silica nanoparticles (Ø26 and 41 nm) and microparticles (Ø1.75 μm) was quantified. At the concentration used (50 μg/ml), silica nanoparticles did not influence cell viability as assessed by MTT assay. Nanoparticle uptake was enhanced in M2-polarized primary human MDM compared with M1 cells, as shown by flow cytometric and microscopic approaches. In contrast, the uptake of microparticles did not differ between M1 and M2 phenotypes. M2 polarization was also associated with increased nanoparticle uptake in the macrophage-like THP-1 cell line. In accordance, in vivo polarized M2-like primary human tumor-associated macrophages obtained from lung tumors took up more nanoparticles than M1-like alveolar macrophages isolated from the surrounding lung tissue. In summary, our data indicate that the M2 polarization of macrophages promotes nanoparticle internalization. Therefore, the phenotypical differences between macrophage subsets should be taken into consideration in future investigations on nanosafety, but

  16. Generation and characterization of bovine bone marrow-derived macrophage cell line.

    PubMed

    Xiao, Jiajia; Xie, Rongxia; Li, Qiaoqiao; Chen, Wuju; Zhang, Yong

    2016-05-01

    Macrophages, as the forefront of innate immune defense, have an important role in the host responses to mycobacterial infection. Therefore, a stable macrophage cell line is needed for future bovine immune system research on the bacterial infection. In this study, we established a bovine macrophage cell line by introducing the human telomerase reverse transcriptase (hTERT) gene into bovine bone marrow-derived macrophages (bBMMs). The TERT-bBMMs cells expressed macrophage surface antigen (CD11b, CD282) and upregulated expression of the cytokines IL-1β, IL-6, IL-10, IL-12, TNF-α in response to bacterial invasion. These results demonstrate that this cell line provide reliable cell model system for future studies on interactions between the bovine macrophages and Mycobacterium tuberculosis. PMID:26936441

  17. Macrophage Inflammatory Assay

    PubMed Central

    Ylostalo, Joni H.

    2016-01-01

    Macrophages represent a widely distributed and functionally diverse population of innate myeloid cells involved in inflammatory response to pathogens, tissue homeostasis and tissue repair (Murray and Wynn, 2011). Macrophages can be broadly grouped into two subpopulations with opposing activites: M1 or pro-inflammatory macrophages that promote T-helper type 1 (Th1) cell immunity and tissue damage, and M2 or anti-inflammatory/alternatively activated macrophages implicated in Th2 response and resolution of inflammation. Here we describe a rapid assay we used previously to monitor changes in pro-inflammatory and anti-inflammatory cytokine production by lipopolysaccharide (LPS)-activated macrophages in response to therapeutic paracrine factors produced by adult stem cells (Bartosh et al., 2010; Ylostalo et al., 2012; Bartosh et al., 2013). The assay can be adapted appropriately to test macrophage response to other agents as well that will be referred to herein as ‘test reagents’ or ‘test compounds’. In this protocol, the mouse macrophage cell line J774A.1 is expanded as an adherent monolayer on petri dishes allowing for the cells to be harvested easily without enzymes or cell scrapers that can damage the cells. The macropahges are then stimulated in suspension with LPS and seeded into 12-well cell culture plates containing the test reagents. After 16–18 h, the medium conditioned by the macrophages is harvested and the cytokine profile in the medium determined with enzyme-linked immunosorbent assays (ELISA). We routinely measure levels of the pro-inflammtory cytokine TNF-alpha and the anti-inflammatory cytokine interleukin-10 (IL-10).

  18. Pulmonary Macrophage Transplantation Therapy

    PubMed Central

    Suzuki, Takuji; Arumugam, Paritha; Sakagami, Takuro; Lachmann, Nico; Chalk, Claudia; Sallese, Anthony; Abe, Shuichi; Trapnell, Cole; Carey, Brenna; Moritz, Thomas; Malik, Punam; Lutzko, Carolyn; Wood, Robert E.; Trapnell, Bruce C.

    2014-01-01

    SUMMARY Bone marrow transplantation is an effective cell therapy but requires myeloablation, which increases infection-risk and mortality. Recent lineage-tracing studies documenting that resident macrophage populations self-maintain independent of hematologic progenitors prompted us to consider organ-targeted, cell-specific therapy. Here, using GM-CSF receptor-β deficient (Csf2rb−/−) mice that develop a myeloid cell disorder identical to hereditary pulmonary alveolar proteinosis (hPAP) in children with CSF2RA/CSF2RB mutations, we show that pulmonary macrophage transplantation (PMT) of either wild-type or Csf2rb-gene-corrected macrophages without myeloablation was safe, well-tolerated, and that one administration corrected the lung disease, secondary systemic manifestations, normalized disease-related biomarkers, and prevented disease-specific mortality. PMT-derived alveolar macrophages persisted for at least one year as did therapeutic effects. Results identify mechanisms regulating alveolar macrophage population size in health and disease, indicate that GM-CSF is required for phenotypic determination of alveolar macrophages, and support translation of PMT as the first specific therapy for children with hPAP. PMID:25274301

  19. The Elusive Antifibrotic Macrophage

    PubMed Central

    Adhyatmika, Adhyatmika; Putri, Kurnia S. S.; Beljaars, Leonie; Melgert, Barbro N.

    2015-01-01

    Fibrotic diseases, especially of the liver, the cardiovascular system, the kidneys, and the lungs, account for approximately 45% of deaths in Western societies. Fibrosis is a serious complication associated with aging and/or chronic inflammation or injury and cannot be treated effectively yet. It is characterized by excessive deposition of extracellular matrix (ECM) proteins by myofibroblasts and impaired degradation by macrophages. This ultimately destroys the normal structure of an organ, which leads to loss of function. Most efforts to develop drugs have focused on inhibiting ECM production by myofibroblasts and have not yielded many effective drugs yet. Another option is to stimulate the cells that are responsible for degradation and uptake of excess ECM, i.e., antifibrotic macrophages. However, macrophages are plastic cells that have many faces in fibrosis, including profibrotic behavior-stimulating ECM production. This can be dependent on their origin, as the different organs have tissue-resident macrophages with different origins and a various influx of incoming monocytes in steady-state conditions and during fibrosis. To be able to pharmacologically stimulate the right kind of behavior in fibrosis, a thorough characterization of antifibrotic macrophages is necessary, as well as an understanding of the signals they need to degrade ECM. In this review, we will summarize the current state of the art regarding the antifibrotic macrophage phenotype and the signals that stimulate its behavior. PMID:26618160

  20. The Elusive Antifibrotic Macrophage.

    PubMed

    Adhyatmika, Adhyatmika; Putri, Kurnia S S; Beljaars, Leonie; Melgert, Barbro N

    2015-01-01

    Fibrotic diseases, especially of the liver, the cardiovascular system, the kidneys, and the lungs, account for approximately 45% of deaths in Western societies. Fibrosis is a serious complication associated with aging and/or chronic inflammation or injury and cannot be treated effectively yet. It is characterized by excessive deposition of extracellular matrix (ECM) proteins by myofibroblasts and impaired degradation by macrophages. This ultimately destroys the normal structure of an organ, which leads to loss of function. Most efforts to develop drugs have focused on inhibiting ECM production by myofibroblasts and have not yielded many effective drugs yet. Another option is to stimulate the cells that are responsible for degradation and uptake of excess ECM, i.e., antifibrotic macrophages. However, macrophages are plastic cells that have many faces in fibrosis, including profibrotic behavior-stimulating ECM production. This can be dependent on their origin, as the different organs have tissue-resident macrophages with different origins and a various influx of incoming monocytes in steady-state conditions and during fibrosis. To be able to pharmacologically stimulate the right kind of behavior in fibrosis, a thorough characterization of antifibrotic macrophages is necessary, as well as an understanding of the signals they need to degrade ECM. In this review, we will summarize the current state of the art regarding the antifibrotic macrophage phenotype and the signals that stimulate its behavior. PMID:26618160

  1. Phagocytic defense in the lung.

    PubMed

    Reynolds, H Y

    1985-01-01

    Phagocytic defense in the normal lung is shared principally by two kinds of cells - alveolar macrophages that reside on the air surface and roam the alveoli and PMNs that circulate in the intravascular space or are stored transiently in areas adjacent to the capillary-alveolar interface (marginated in capillaries) and can reach the alveolar space quickly. The nature of the stimulating microorganism or aerosol particle reaching the alveolar surface may determine which phagocytic cell ultimately responds to contain the intruder. Ingestion and containment (either intracellular killing or enzymatic degradation) are the goals, and an 'opsonin' may be necessary to enhance the efficiency of phagocytosis. In the lung this is very complex, reflecting the interdependence on immune and nonimmune opsonins. For immune mediated phagocytosis by alveolar macrophages, IgG antibody is preferable. Among the four subclasses of IgG, certain ones seem to bind preferentially to macrophages, whereas others are already adherent to the cells as cytophilic antibody. In the respiratory tract milieu of subjects with CF, the interaction of immune and nonimmune opsonins is much more complex because of proteolytic enzymes that can degrade antibodies creating various fragments. Now that we are in an era of very specific humoral replacement therapy with intravenous IgG that contains IgG subclasses and the potential for using monoclonal antibodies for very precisely directed replacement, special attention must be given to identifying the appropriate class and subclass of antibody that may be required. This may be relatively simple when forms of passive immune therapy are being considered. More difficult will be devising ways to actively immunize patients (or animals) and manipulate their antibody responses so that selective immunoglobulin subclasses are produced. To obtain such control over the humoral immune response will require much more basic work in animal models. More attention to the form of

  2. Technologies for Distributed Defense

    SciTech Connect

    Seiders, Barbara AB; Rybka, Anthony J.

    2002-07-01

    For Americans, the nature of warfare changed on September 11, 2001. Our national security henceforth will require distributed defense. One extreme of distributed defense is represented by fully deployed military troops responding to a threat from a hostile nation state. At the other extreme is a country of "citizen soldiers," with families and communities securing their common defense through heightened awareness, engagement as good neighbors, and local support of and cooperation with local law enforcement, emergency and health care providers. Technologies - for information exploitation, biological agent detection, health care surveillance, and security - will be critical to ensuring success in distributed defense.

  3. Type I interferon induces necroptosis in macrophages during infection with Salmonella enterica serovar Typhimurium

    PubMed Central

    Robinson, Nirmal; McComb, Scott; Mulligan, Rebecca; Dudani, Renu; Krishnan, Lakshmi; Sad, Subash

    2014-01-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is a virulent pathogen that induces rapid host death. Here we observed that host survival after infection with S. Typhimurium was enhanced in the absence of type I interferon signaling, with improved survival of mice deficient in the receptor for type I interferons (Ifnar1−/− mice) that was attributed to macrophages. Although there was no impairment in cytokine expression or inflammasome activation in Ifnar1−/− macrophages, they were highly resistant to S. Typhimurium–induced cell death. Specific inhibition of the kinase RIP1or knockdown of the gene encoding the kinase RIP3 prevented the death of wild-type macrophages, which indicated that necroptosis was a mechanism of cell death. Finally, RIP3-deficient macrophages, which cannot undergo necroptosis, had similarly less death and enhanced control of S. Typhimurium in vivo. Thus, we propose that S. Typhimurium induces the production of type I interferon, which drives necroptosis of macrophages and allows them to evade the immune response. PMID:22922364

  4. Synthetic cationic peptide IDR-1018 modulates human macrophage differentiation.

    PubMed

    Pena, Olga M; Afacan, Nicole; Pistolic, Jelena; Chen, Carol; Madera, Laurence; Falsafi, Reza; Fjell, Christopher D; Hancock, Robert E W

    2013-01-01

    Macrophages play a critical role in the innate immune response. To respond in a rapid and efficient manner to challenges in the micro-environment, macrophages are able to differentiate towards classically (M1) or alternatively (M2) activated phenotypes. Synthetic, innate defense regulators (IDR) peptides, designed based on natural host defence peptides, have enhanced immunomodulatory activities and reduced toxicity leading to protection in infection and inflammation models that is dependent on innate immune cells like monocytes/macrophages. Here we tested the effect of IDR-1018 on macrophage differentiation, a process essential to macrophage function and the immune response. Using transcriptional, protein and systems biology analysis, we observed that differentiation in the presence of IDR-1018 induced a unique signature of immune responses including the production of specific pro and anti-inflammatory mediators, expression of wound healing associated genes, and increased phagocytosis of apoptotic cells. Transcription factor IRF4 appeared to play an important role in promoting this IDR-1018-induced phenotype. The data suggests that IDR-1018 drives macrophage differentiation towards an intermediate M1-M2 state, enhancing anti-inflammatory functions while maintaining certain pro-inflammatory activities important to the resolution of infection. Synthetic peptides like IDR-1018, which act by modulating the immune system, could represent a powerful new class of therapeutics capable of treating the rising number of multidrug resistant infections as well as disorders associated with dysregulated immune responses. PMID:23308112

  5. Flies evade looming targets by executing rapid visually directed banked turns.

    PubMed

    Muijres, Florian T; Elzinga, Michael J; Melis, Johan M; Dickinson, Michael H

    2014-04-11

    Avoiding predators is an essential behavior in which animals must quickly transform sensory cues into evasive actions. Sensory reflexes are particularly fast in flying insects such as flies, but the means by which they evade aerial predators is not known. Using high-speed videography and automated tracking of flies in combination with aerodynamic measurements on flapping robots, we show that flying flies react to looming stimuli with directed banked turns. The maneuver consists of a rapid body rotation followed immediately by an active counter-rotation and is enacted by remarkably subtle changes in wing motion. These evasive maneuvers of flies are substantially faster than steering maneuvers measured previously and indicate the existence of sensory-motor circuitry that can reorient the fly's flight path within a few wingbeats. PMID:24723606

  6. A hot L1 retrotransposon evades somatic repression and initiates human colorectal cancer.

    PubMed

    Scott, Emma C; Gardner, Eugene J; Masood, Ashiq; Chuang, Nelson T; Vertino, Paula M; Devine, Scott E

    2016-06-01

    Although human LINE-1 (L1) elements are actively mobilized in many cancers, a role for somatic L1 retrotransposition in tumor initiation has not been conclusively demonstrated. Here, we identify a novel somatic L1 insertion in the APC tumor suppressor gene that provided us with a unique opportunity to determine whether such insertions can actually initiate colorectal cancer (CRC), and if so, how this might occur. Our data support a model whereby a hot L1 source element on Chromosome 17 of the patient's genome evaded somatic repression in normal colon tissues and thereby initiated CRC by mutating the APC gene. This insertion worked together with a point mutation in the second APC allele to initiate tumorigenesis through the classic two-hit CRC pathway. We also show that L1 source profiles vary considerably depending on the ancestry of an individual, and that population-specific hot L1 elements represent a novel form of cancer risk. PMID:27197217

  7. Evading the pulsar constraints on the cosmic string tension in supergravity inflation

    SciTech Connect

    Kamada, Kohei; Miyamoto, Yuhei; Yokoyama, Jun'ichi E-mail: miyamoto@resceu.s.u-tokyo.ac.jp

    2012-10-01

    The cosmic string is a useful probe of the early Universe and may give us a clue to physics at high energy scales which particle accelerators cannot reach. Although the most promising tool to observe it is the cosmic microwave background (CMB), the constraint from gravitational waves is becoming so stringent that detecting its signatures in CMB may be impossible. In this paper, we construct a scenario that contains cosmic strings observable in the cosmic microwave background while evading the constraint imposed by the recent pulsar timing data. We argue that cosmic strings with relatively large tension are allowed by diluting loops contributing to the relevant frequency range of the gravitational wave background. We also present a particle physics model to realize such dilution in the context of chaotic inflation in supergravity, where the phase transition occurs during inflation due to the time-dependence of the Hubble induced mass.

  8. Mycobacterium leprae-Infected Macrophages Preferentially Primed Regulatory T Cell Responses and Was Associated with Lepromatous Leprosy

    PubMed Central

    Miranda, Jake W.; Gilson, Danny J.; Song, Zhengyu; Chen, Jia; Shi, Chao; Zhu, Jianyu; Yang, Jun; Jing, Zhichun

    2016-01-01

    Background The persistence of Mycobacterium leprae (M. leprae) infection is largely dependent on the types of host immune responses being induced. Macrophage, a crucial modulator of innate and adaptive immune responses, could be directly infected by M. leprae. We therefore postulated that M. leprae-infected macrophages might have altered immune functions. Methodology/Principal Findings Here, we treated monocyte-derived macrophages with live or killed M. leprae, and examined their activation status and antigen presentation. We found that macrophages treated with live M. leprae showed committed M2-like function, with decreased interleukin 1 beta (IL-1beta), IL-6, tumor necrosis factor alpha (TNF-alpha) and MHC class II molecule expression and elevated IL-10 and CD163 expression. When incubating with naive T cells, macrophages treated with live M. leprae preferentially primed regulatory T (Treg) cell responses with elevated FoxP3 and IL-10 expression, while interferon gamma (IFN-gamma) expression and CD8+ T cell cytotoxicity were reduced. Chromium release assay also found that live M. leprae-treated macrophages were more resistant to CD8+ T cell-mediated cytotoxicity than sonicated M. leprae-treated monocytes. Ex vivo studies showed that the phenotype and function of monocytes and macrophages had clear differences between L-lep and T-lep patients, consistent with the in vitro findings. Conclusions/Significance Together, our data demonstrate that M. leprae could utilize infected macrophages by two mechanisms: firstly, M. leprae-infected macrophages preferentially primed Treg but not Th1 or cytotoxic T cell responses; secondly, M. leprae-infected macrophages were more effective at evading CD8+ T cell-mediated cytotoxicity. PMID:26751388

  9. 22 CFR 130.4 - Defense articles and defense services.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Defense articles and defense services. 130.4 Section 130.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS POLITICAL CONTRIBUTIONS, FEES AND COMMISSIONS § 130.4 Defense articles and defense services. Defense articles and...

  10. 22 CFR 130.4 - Defense articles and defense services.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Defense articles and defense services. 130.4 Section 130.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS POLITICAL CONTRIBUTIONS, FEES AND COMMISSIONS § 130.4 Defense articles and defense services. Defense articles and...

  11. 22 CFR 130.4 - Defense articles and defense services.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Defense articles and defense services. 130.4 Section 130.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS POLITICAL CONTRIBUTIONS, FEES AND COMMISSIONS § 130.4 Defense articles and defense services. Defense articles and...

  12. 22 CFR 130.4 - Defense articles and defense services.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Defense articles and defense services. 130.4 Section 130.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS POLITICAL CONTRIBUTIONS, FEES AND COMMISSIONS § 130.4 Defense articles and defense services. Defense articles and...

  13. 22 CFR 130.4 - Defense articles and defense services.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Defense articles and defense services. 130.4 Section 130.4 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS POLITICAL CONTRIBUTIONS, FEES AND COMMISSIONS § 130.4 Defense articles and defense services. Defense articles and...

  14. Rabies Virus Nucleoprotein Functions To Evade Activation of the RIG-I-Mediated Antiviral Response▿

    PubMed Central

    Masatani, Tatsunori; Ito, Naoto; Shimizu, Kenta; Ito, Yuki; Nakagawa, Keisuke; Sawaki, Yoshiharu; Koyama, Hiroyuki; Sugiyama, Makoto

    2010-01-01

    The rabies virus Ni-CE strain causes nonlethal infection in adult mice after intracerebral inoculation, whereas the parental Nishigahara (Ni) strain kills mice. We previously reported that the chimeric CE(NiN) strain with the N gene from the Ni strain in the genetic background of the Ni-CE strain kills adult mice, indicating that the N gene is related to the different pathogenicities of Ni and Ni-CE strains. In the present study, to obtain an insight into the mechanism by which the N gene determines viral pathogenicity, we compared the effects of Ni, Ni-CE, and CE(NiN) infections on host gene expressions using a human neuroblastoma cell line. Microarray analysis of these infected cells revealed that the expression levels of particular genes in Ni- and CE(NiN)-infected cells, including beta interferon (IFN-β) and chemokine genes (i.e., CXCL10 and CCL5) were lower than those in Ni-CE-infected cells. We also demonstrated that Ni-CE infection activated the interferon regulatory factor 3 (IRF-3)-dependent IFN-β promoter and induced IRF-3 nuclear translocation more efficiently than did Ni or CE(NiN) infection. Furthermore, we showed that Ni-CE infection, but not Ni or CE(NiN) infection, strongly activates the IRF-3 pathway through activation of RIG-I, which is known as a cellular sensor of virus infection. These findings indicate that the N protein of rabies virus (Ni strain) has a function to evade the activation of RIG-I. To our knowledge, this is the first report that the Mononegavirales N protein functions to evade induction of host IFN and chemokines. PMID:20130065

  15. Schools and Civil Defense.

    ERIC Educational Resources Information Center

    Office of Civil Defense (DOD), Washington, DC.

    Civil defense is a planned, coordinated action to protect the population during any emergency whether arising from thermonuclear attack or natural disaster. The Federal Government has assumed four responsibilities--(1) to keep track of the nature of the threat which the civil defense program must meet, (2) to prepare and disseminate information…

  16. Forgiveness and Defense Style

    ERIC Educational Resources Information Center

    Maltby, John; Day, Liz

    2004-01-01

    Within the literature on the psychology of forgiveness, researchers have hypothesized that the 1st stage in the process of being able to forgive is the role of psychological defense. To examine such a hypothesis, the authors explored the relationship between forgiveness and defense style. The 304 respondents (151 men, 153 women) completed measures…

  17. Defense Mechanisms: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    This bibliography includes studies of defense mechanisms, in general, and studies of multiple mechanisms. Defense mechanisms, briefly and simply defined, are the unconscious ego defendants against unpleasure, threat, or anxiety. Sigmund Freud deserves the clinical credit for studying many mechanisms and introducing them in professional literature.…

  18. ENHANCED BINDING OF AUTOLOGOUS RED CELLS TO THE MACROPHAGE PLASMA MEMBRANE AS A SENSITIVE INDICATOR OF POLLUTANT DAMAGE

    EPA Science Inventory

    The alveolar macrophage (AM) represents the primary line of defense in host protection against inhaled infectious organisms. Following exposure to oxidant gases, the ability of the host to resist airborne bacterial infection is severely impaired, and damage to the AM defense syst...

  19. Immunoproteasome dysfunction augments alternative polarization of alveolar macrophages.

    PubMed

    Chen, S; Kammerl, I E; Vosyka, O; Baumann, T; Yu, Y; Wu, Y; Irmler, M; Overkleeft, H S; Beckers, J; Eickelberg, O; Meiners, S; Stoeger, T

    2016-06-01

    The proteasome is a central regulatory hub for intracellular signaling by degrading numerous signaling mediators. Immunoproteasomes are specialized types of proteasomes involved in shaping adaptive immune responses, but their role in innate immune signaling is still elusive. Here, we analyzed immunoproteasome function for polarization of alveolar macrophages, highly specialized tissue macrophages of the alveolar lung surface. Classical activation (M1 polarization) of primary alveolar macrophages by LPS/IFNγ transcriptionally induced all three immunoproteasome subunits, low molecular mass protein 2 (LMP2), LMP7 and multicatalytic endopeptidase complex-like 1, which was accompanied by increased immunoproteasome activity in M1 cells. Deficiency of LMP7 had no effect on the LPS/IFNγ-triggered M1 profile indicating that immunoproteasome function is dispensable for classical alveolar macrophage activation. In contrast, IL-4 triggered alternative (M2) activation of primary alveolar macrophages was accompanied by a transcriptionally independent amplified expression of LMP2 and LMP7 and an increase in immunoproteasome activity. Alveolar macrophages from LMP7 knockout mice disclosed a distorted M2 profile upon IL-4 stimulation as characterized by increased M2 marker gene expression and CCL17 cytokine release. Comparative transcriptome analysis revealed enrichment of IL-4-responsive genes and of genes involved in cellular response to defense, wounding and inflammation in LMP7-deficient alveolar macrophages indicating a distinct M2 inflammation resolving phenotype. Moreover, augmented M2 polarization was accompanied by amplified AKT/STAT6 activation and increased RNA and protein expression of the M2 master transcription factor interferon regulatory factor 4 in LMP7(-/-) alveolar macrophages. IL-13 stimulation of LMP7-deficient macrophages induced a similar M2-skewed profile indicative for augmented signaling via the IL-4 receptor α (IL4Rα). IL4Rα expression was generally

  20. Macrophage takeover and the host-bacilli interplay during tuberculosis.

    PubMed

    Hussain Bhat, Khalid; Mukhopadhyay, Sangita

    2015-01-01

    Macrophages are key type of antigen-presenting cells that arbitrate the first line of defense against various intracellular pathogens. Tuberculosis, both pulmonary and extrapulmonary, is an infectious disease of global concern caused by Mycobacterium tuberculosis. The bacillus is a highly successful pathogen and has acquired various strategies to downregulate critical innate-effector immune responses of macrophages, such as phagosome-lysosome fusion, autophagy, induction of cytokines, generation of reactive oxygen and nitrogen species and antigen presentation. In addition, the bacilli also subvert acquired immunity. In this review, we aim to provide an overview of different antimycobacterial immune functions of macrophage and the strategies adopted by the bacilli to manipulate these functions to favor its survival and replication inside the host. PMID:26000654

  1. Two systems and defenses.

    PubMed

    Novick, Jack; Novick, Kerry Kelly

    2013-02-01

    The authors suggest that Freud's concept of defense differentiated psychoanalysis from other medical and psychological theories of personality development and functioning then and now. Reclaiming the concept's centrality and linking it with interdisciplinary research findings, they illustrate their extension of defense into a two-system model of self-protection and self-regulation with a clinical example. The authors suggest that the two-system model allows for the reintegration of defense into a multidimensional psychoanalytic theory and multimodal therapeutic technique. PMID:23421665

  2. M1 and M2 Macrophages: The Chicken and the Egg of Immunity

    PubMed Central

    Mills, Charles D.; Ley, Klaus

    2015-01-01

    The purpose of this perspective is to describe a critical advance in understanding how immune responses work. Macrophages are required for all animal life: ‘Inhibit’ type macrophages in all animals (called M1) can rapidly kill pathogens, and are thus the primary host defense, and ‘Heal’ type macrophages (M2) routinely repair and maintain tissue integrity. Macrophages perform these activities in all animals without T cells, and also in T cell-deficient vertebrates. Although adaptive immunity can amplify macrophage polarization, the long-held notion that macrophages need to be ‘activated’ or ‘alternatively activated’ by T cells is incorrect; indeed, immunology has had it backward. M1/M2-type macrophages necessarily direct T cells toward Th1- or Th2-like activities, respectively. That such macrophage-innate activities are the central directing element in immune responses is a dramatic change in understanding how immune systems operate. Most important, this revelation is opening up whole new approaches to immunotherapy. For example, many modern diseases, such as cancer and atherosclerosis, may not display ‘foreign’ antigens. However, there are clear imbalances in M1/M2-type responses. Correcting such innate imbalances can result in better health. Macrophages are the chicken and the egg of immunity. PMID:25138714

  3. Neutrophil Migration into the Infected Uroepithelium Is Regulated by the Crosstalk between Resident and Helper Macrophages

    PubMed Central

    Zec, Kristina; Volke, Julia; Vijitha, Nirojah; Thiebes, Stephanie; Gunzer, Matthias; Kurts, Christian; Engel, Daniel Robert

    2016-01-01

    The antibacterial defense against infections depends on the cooperation between distinct phagocytes of the innate immune system, namely macrophages and neutrophils. However, the mechanisms driving this cooperation are incompletely understood. In this study we describe the crosstalk between Ly6C+ and Ly6C− macrophage-subtypes and neutrophils in the context of urinary tract infection (UTI) with uropathogenic E. coli (UPEC). Ly6C− macrophages acted as tissue resident sentinels and attracted circulating phagocytes by chemokines. Ly6C+ macrophages produced tumor necrosis factor (TNF) that licensed Ly6C− macrophages to release preformed CXCL2, which in turn caused matrix metalloproteinases (MMP-9) secretion by neutrophils to enable transepithelial migration. PMID:26861402

  4. Co-existence of classical and alternative activation programs in macrophages responding to Toxoplasma gondii

    PubMed Central

    Patil, Veerupaxagouda; Zhao, Yanlin; Shah, Suhagi; Fox, Barbara A.; Rommereim, Leah M.; Bzik, David J.; Yap, George S.

    2013-01-01

    Pro-inflammatory M1 macrophages are critical for defense against intracellular pathogens while alternatively-activated M2 macrophages mediate tissue homeostasis and repair. Whether these distinct activation programs are mutually exclusive or can co-exist within the same cell is unclear. Here, we report the co-existence of these programs in Toxoplasma gondii-elicited inflammatory macrophages. This is independent of parasite expression of the virulence factor ROP16 and host cell expression of signal transducer and activator of transcription 6 (STAT6). Furthermore, this observation was recapitulated by IFN-γ and IL-4 treated bone marrow-derived macrophages in vitro. These results highlight the multi-functionality of macrophages as they respond to diverse microbial and endogenous stimuli. PMID:24083945

  5. Co-existence of classical and alternative activation programs in macrophages responding to Toxoplasma gondii.

    PubMed

    Patil, Veerupaxagouda; Zhao, Yanlin; Shah, Suhagi; Fox, Barbara A; Rommereim, Leah M; Bzik, David J; Yap, George S

    2014-02-01

    Pro-inflammatory M1 macrophages are critical for defense against intracellular pathogens while alternatively-activated M2 macrophages mediate tissue homeostasis and repair. Whether these distinct activation programs are mutually exclusive or can co-exist within the same cell is unclear. Here, we report the co-existence of these programs in Toxoplasma gondii-elicited inflammatory macrophages. This is independent of parasite expression of the virulence factor ROP16 and host cell expression of signal transducer and activator of transcription 6 (STAT6). Furthermore, this observation was recapitulated by IFN-γ and IL-4 treated bone marrow-derived macrophages in vitro. These results highlight the multi-functionality of macrophages as they respond to diverse microbial and endogenous stimuli. PMID:24083945

  6. IL-33 Priming Enhances Peritoneal Macrophage Activity in Response to Candida albicans.

    PubMed

    Tran, Vuvi G; Cho, Hong R; Kwon, Byungsuk

    2014-08-01

    IL-33 is a member of the IL-1 cytokine family and plays a role in the host defense against bacteria, viruses, and fungi. In this study, we investigated the function of IL-33 and its receptor in in vitro macrophage responses to Candida albicans. Our results demonstrate that pre-sensitization of isolated peritoneal macrophages with IL-33 enhanced their pro-inflammatory cytokine production and phagocytic activity in response to C. albicans. These macrophage activities were entirely dependent on the ST2-MyD88 signaling pathway. In addition, pre-sensitization with IL-33 also increased ROS production and the subsequent killing ability of macrophages following C. albicans challenge. These results indicate that IL-33 may increase anti-fungal activity against Candida through macrophage-mediated resistance mechanisms. PMID:25177252

  7. Wormhole Travel for Macrophages.

    PubMed

    Okabe, Yasutaka; Medzhitov, Ruslan

    2016-04-21

    Leukocyte recruitment is generally achieved by rapid migration of inflammatory cells out of circulation, through modified blood vessels, and into affected tissues. Now, Wang and Kubes show that macrophages can be rapidly recruited from body cavities to the liver, via a non-vascular route, where they help to coordinate tissue repair. PMID:27104973

  8. IFN-γ Prevents Adenosine Receptor (A2bR) Upregulation To Sustain the Macrophage Activation Response.

    PubMed

    Cohen, Heather B; Ward, Amanda; Hamidzadeh, Kajal; Ravid, Katya; Mosser, David M

    2015-10-15

    The priming of macrophages with IFN-γ prior to TLR stimulation results in enhanced and prolonged inflammatory cytokine production. In this study, we demonstrate that, following TLR stimulation, macrophages upregulate the adenosine 2b receptor (A2bR) to enhance their sensitivity to immunosuppressive extracellular adenosine. This upregulation of A2bR leads to the induction of macrophages with an immunoregulatory phenotype and the downregulation of inflammation. IFN-γ priming of macrophages selectively prevents the induction of the A2bR in macrophages to mitigate sensitivity to adenosine and to prevent this regulatory transition. IFN-γ-mediated A2bR blockade leads to a prolonged production of TNF-α and IL-12 in response to TLR ligation. The pharmacologic inhibition or the genetic deletion of the A2bR results in a hyperinflammatory response to TLR ligation, similar to IFN-γ treatment of macrophages. Conversely, the overexpression of A2bR on macrophages blunts the IFN-γ effects and promotes the development of immunoregulatory macrophages. Thus, we propose a novel mechanism whereby IFN-γ contributes to host defense by desensitizing macrophages to the immunoregulatory effects of adenosine. This mechanism overcomes the transient nature of TLR activation, and prolongs the antimicrobial state of the classically activated macrophage. This study may offer promising new targets to improve the clinical outcome of inflammatory diseases in which macrophage activation is dysregulated. PMID:26355158

  9. Alterations in macrophage functions by environmental chemicals.

    PubMed Central

    Gardner, D E

    1984-01-01

    The establishment of infectious diseases is rarely entirely attributed to a single entity, but instead is the result of a primary stress and one or more secondary factors that interfere with homeostasis and the ability of the host to cope with the primary etiologic assault. Any environmental chemical that can suppress the normal functioning of the host's body defenses would be expected to increase the risk of the host to such diseases. Within the lung, the alveolar macrophages are the crucial elements responsible for defending the body against such airborne viable agents. The effects of inhaled gases and particulates on these defense cells are a major concern of the environmental health scientist since such chemicals have the capability of adversely affecting the integrity and functioning of these pulmonary defense cells. The objective of this report is to provide an overview that will improve our understanding of how a variety of environmental chemicals can alter the biochemical, physiological and immunological functioning of these cells. PMID:6376106

  10. Transcriptional Regulation and Macrophage Differentiation.

    PubMed

    Hume, David A; Summers, Kim M; Rehli, Michael

    2016-06-01

    Monocytes and macrophages are professional phagocytes that occupy specific niches in every tissue of the body. Their survival, proliferation, and differentiation are controlled by signals from the macrophage colony-stimulating factor receptor (CSF-1R) and its two ligands, CSF-1 and interleukin-34. In this review, we address the developmental and transcriptional relationships between hematopoietic progenitor cells, blood monocytes, and tissue macrophages as well as the distinctions from dendritic cells. A huge repertoire of receptors allows monocytes, tissue-resident macrophages, or pathology-associated macrophages to adapt to specific microenvironments. These processes create a broad spectrum of macrophages with different functions and individual effector capacities. The production of large transcriptomic data sets in mouse, human, and other species provides new insights into the mechanisms that underlie macrophage functional plasticity. PMID:27337479

  11. Hydrogen Peroxide Produced by Oral Streptococci Induces Macrophage Cell Death

    PubMed Central

    Okahashi, Nobuo; Nakata, Masanobu; Sumitomo, Tomoko; Terao, Yutaka; Kawabata, Shigetada

    2013-01-01

    Hydrogen peroxide (H2O2) produced by members of the mitis group of oral streptococci plays important roles in microbial communities such as oral biofilms. Although the cytotoxicity of H2O2 has been widely recognized, the effects of H2O2 produced by oral streptococci on host defense systems remain unknown. In the present study, we investigated the effect of H2O2 produced by Streptococcus oralis on human macrophage cell death. Infection by S. oralis was found to stimulate cell death of a THP-1 human macrophage cell line at multiplicities of infection greater than 100. Catalase, an enzyme that catalyzes the decomposition of H2O2, inhibited the cytotoxic effect of S. oralis. S. oralis deletion mutants lacking the spxB gene, which encodes pyruvate oxidase, and are therefore deficient in H2O2 production, showed reduced cytotoxicity toward THP-1 macrophages. Furthermore, H2O2 alone was capable of inducing cell death. The cytotoxic effect seemed to be independent of inflammatory responses, because H2O2 was not a potent stimulator of tumor necrosis factor-α production in macrophages. These results indicate that streptococcal H2O2 plays a role as a cytotoxin, and is implicated in the cell death of infected human macrophages. PMID:23658745

  12. Characterization of two porcine macrophage cell lines for the expression of pathogen-recognition receptors, defensins, cytokines, chemokines, and surface sialic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Macrophages express various pathogen-recognition receptors (PRRs) which recognize pathogen-associated molecular patterns (PAMPs) and activate genes responsible for host defense. The aim of this study was to characterize two porcine macrophage cell lines (Cdelta+ and Cdelta–) for the expression of P...

  13. Macrophage infection models for Mycobacterium tuberculosis.

    PubMed

    Johnson, Benjamin K; Abramovitch, Robert B

    2015-01-01

    Mycobacterium tuberculosis colonizes, survives, and grows inside macrophages. In vitro macrophage infection models, using both primary macrophages and cell lines, enable the characterization of the pathogen response to macrophage immune pressure and intracellular environmental cues. We describe methods to propagate and infect primary murine bone marrow-derived macrophages and J774 and THP-1 macrophage-like cell lines. We also present methods on the characterization of M. tuberculosis intracellular survival and the preparation of infected macrophages for imaging. PMID:25779326

  14. A novel real time imaging platform to quantify macrophage phagocytosis.

    PubMed

    Kapellos, Theodore S; Taylor, Lewis; Lee, Heyne; Cowley, Sally A; James, William S; Iqbal, Asif J; Greaves, David R

    2016-09-15

    Phagocytosis of pathogens, apoptotic cells and debris is a key feature of macrophage function in host defense and tissue homeostasis. Quantification of macrophage phagocytosis in vitro has traditionally been technically challenging. Here we report the optimization and validation of the IncuCyte ZOOM® real time imaging platform for macrophage phagocytosis based on pHrodo® pathogen bioparticles, which only fluoresce when localized in the acidic environment of the phagolysosome. Image analysis and fluorescence quantification were performed with the automated IncuCyte™ Basic Software. Titration of the bioparticle number showed that the system is more sensitive than a spectrofluorometer, as it can detect phagocytosis when using 20× less E. coli bioparticles. We exemplified the power of this real time imaging platform by studying phagocytosis of murine alveolar, bone marrow and peritoneal macrophages. We further demonstrate the ability of this platform to study modulation of the phagocytic process, as pharmacological inhibitors of phagocytosis suppressed bioparticle uptake in a concentration-dependent manner, whereas opsonins augmented phagocytosis. We also investigated the effects of macrophage polarization on E. coli phagocytosis. Bone marrow-derived macrophage (BMDM) priming with M2 stimuli, such as IL-4 and IL-10 resulted in higher engulfment of bioparticles in comparison with M1 polarization. Moreover, we demonstrated that tolerization of BMDMs with lipopolysaccharide (LPS) results in impaired E. coli bioparticle phagocytosis. This novel real time assay will enable researchers to quantify macrophage phagocytosis with a higher degree of accuracy and sensitivity and will allow investigation of limited populations of primary phagocytes in vitro. PMID:27475716

  15. [The current situation of aggravated intoxication with "kiken" drugs (law-evading drugs)].

    PubMed

    Akashi, Akiko; Kashiura, Masahiro; Mikami, Manabu; Hamabe, Yuichi

    2016-03-01

    The intoxication caused by "kiken" drugs (law-evading drugs), such as synthetic cannabinoids, cathinones, and methoxetamine, has recently increased in Japan. We retrospectively examined the characteristics of patients poisoned with the "kiken" drugs. We included patients who presented at the emergency department at the Tokyo Metropolitan Bokutoh Hospital from January 2011 to December 2014. Eighteen patients admitted between January 2011 and December 2013 were included in the early period group and 10 patients admitted between January and December 2014 were categorized into the late period group. The number of the patients transported to our emergency department between 2011 and 2014 increased annually. Patients were mainly admitted between May and October 2014; no patients were admitted after November 2014. The patients' age, history of previous mental disease, habitual use, Triage DOA results, serum creatinine values on admission, and respiratory management differed significantly between the groups. However, the median serum creatinine values of both groups on admission were within the normal level. Patients poisoned with the "kiken" drugs showed more severe symptoms, higher rate of habitual use, and higher average age. The annual increase in the number of the patients observed thus far is expected to decrease in the future. Maintenance of the law and expansion of medical institutions that treat patients addicted to the "kiken" drugs are warranted. PMID:27255020

  16. The Plasmodium falciparum blood stages acquire factor H family proteins to evade destruction by human complement.

    PubMed

    Rosa, Thiago F A; Flammersfeld, Ansgar; Ngwa, Che J; Kiesow, Meike; Fischer, Rainer; Zipfel, Peter F; Skerka, Christine; Pradel, Gabriele

    2016-04-01

    The acquisition of regulatory proteins is a means of blood-borne pathogens to avoid destruction by the human complement. We recently showed that the gametes of the human malaria parasite Plasmodium falciparum bind factor H (FH) from the blood meal of the mosquito vector to assure successful sexual reproduction, which takes places in the mosquito midgut. While these findings provided a first glimpse of a complex mechanism used by Plasmodium to control the host immune attack, it is hitherto not known, how the pathogenic blood stages of the malaria parasite evade destruction by the human complement. We now show that the human complement system represents a severe threat for the replicating blood stages, particularly for the reinvading merozoites, with complement factor C3b accumulating on the surfaces of the intraerythrocytic schizonts as well as of free merozoites. C3b accumulation initiates terminal complement complex formation, in consequence resulting in blood stage lysis. To inactivate C3b, the parasites bind FH as well as related proteins FHL-1 and CFHR-1 to their surface, and FH binding is trypsin-resistant. Schizonts acquire FH via two contact sites, which involve CCP modules 5 and 20. Blockage of FH-mediated protection via anti-FH antibodies results in significantly impaired blood stage replication, pointing to the plasmodial complement evasion machinery as a promising malaria vaccine target. PMID:26457721

  17. Leukemic Stem Cells Evade Chemotherapy by Metabolic Adaptation to an Adipose Tissue Niche.

    PubMed

    Ye, Haobin; Adane, Biniam; Khan, Nabilah; Sullivan, Timothy; Minhajuddin, Mohammad; Gasparetto, Maura; Stevens, Brett; Pei, Shanshan; Balys, Marlene; Ashton, John M; Klemm, Dwight J; Woolthuis, Carolien M; Stranahan, Alec W; Park, Christopher Y; Jordan, Craig T

    2016-07-01

    Adipose tissue (AT) has previously been identified as an extra-medullary reservoir for normal hematopoietic stem cells (HSCs) and may promote tumor development. Here, we show that a subpopulation of leukemic stem cells (LSCs) can utilize gonadal adipose tissue (GAT) as a niche to support their metabolism and evade chemotherapy. In a mouse model of blast crisis chronic myeloid leukemia (CML), adipose-resident LSCs exhibit a pro-inflammatory phenotype and induce lipolysis in GAT. GAT lipolysis fuels fatty acid oxidation in LSCs, especially within a subpopulation expressing the fatty acid transporter CD36. CD36(+) LSCs have unique metabolic properties, are strikingly enriched in AT, and are protected from chemotherapy by the GAT microenvironment. CD36 also marks a fraction of human blast crisis CML and acute myeloid leukemia (AML) cells with similar biological properties. These findings suggest striking interplay between leukemic cells and AT to create a unique microenvironment that supports the metabolic demands and survival of a distinct LSC subpopulation. PMID:27374788

  18. Generation of a squeezed state of an oscillator by stroboscopic back-action-evading measurement

    NASA Astrophysics Data System (ADS)

    Vasilakis, G.; Shen, H.; Jensen, K.; Balabas, M.; Salart, D.; Chen, B.; Polzik, E. S.

    2015-05-01

    Continuous observation of an oscillator results in quantum back-action, which limits the knowledge acquired by the measurement. A careful balance between the information obtained and the back-action disturbance leads to the standard quantum limit of precision. This limit can be surpassed by a measurement with strength modulated at twice the oscillator frequency, resulting in a squeezed state of the oscillator motion, as proposed decades ago. Here, we report the generation of a squeezed state of an oscillator by a stroboscopic back-action-evading measurement. The oscillator is the spin of an atomic ensemble precessing in a magnetic field. The oscillator initially prepared nearly in the ground state is stroboscopically coupled to an optical mode of a cavity. A measurement of the output light results in a 2.2 +/- 0.3 dB squeezed state of the oscillator. The demonstrated spin-squeezed state of 108 atoms with an angular spin variance of 8 × 10-10 rad2 is promising for magnetic field sensing.

  19. Evading Quantum Mechanics: Engineering a Classical Subsystem within a Quantum Environment

    NASA Astrophysics Data System (ADS)

    Tsang, Mankei; Caves, Carlton M.

    2012-07-01

    Quantum mechanics is potentially advantageous for certain information-processing tasks, but its probabilistic nature and requirement of measurement backaction often limit the precision of conventional classical information-processing devices, such as sensors and atomic clocks. Here we show that, by engineering the dynamics of coupled quantum systems, it is possible to construct a subsystem that evades the measurement backaction of quantum mechanics, at all times of interest, and obeys any classical dynamics, linear or nonlinear, that we choose. We call such a system a quantum-mechanics-free subsystem (QMFS). All of the observables of a QMFS are quantum-nondemolition (QND) observables; moreover, they are dynamical QND observables, thus demolishing the widely held belief that QND observables are constants of motion. QMFSs point to a new strategy for designing classical information-processing devices in regimes where quantum noise is detrimental, unifying previous approaches that employ QND observables, backaction evasion, and quantum noise cancellation. Potential applications include gravitational-wave detection, optomechanical-force sensing, atomic magnetometry, and classical computing. Demonstrations of dynamical QMFSs include the generation of broadband squeezed light for use in interferometric gravitational-wave detection, experiments using entangled atomic-spin ensembles, and implementations of the quantum Toffoli gate.

  20. Human Immunodeficiency Virus Infection and Host Defense in the Lungs.

    PubMed

    Charles, Tysheena P; Shellito, Judd E

    2016-04-01

    Immunosuppression associated with human immunodeficiency virus (HIV) infection impacts all components of host defense against pulmonary infection. Cells within the lung have altered immune function and are important reservoirs for HIV infection. The host immune response to infected lung cells further compromises responses to a secondary pathogenic insult. In the upper respiratory tract, mucociliary function is impaired and there are decreased levels of salivary immunoglobulin A. Host defenses in the lower respiratory tract are controlled by alveolar macrophages, lymphocytes, and polymorphonuclear leukocytes. As HIV infection progresses, lung CD4 T cells are reduced in number causing a lack of activation signals from CD4 T cells and impaired defense by macrophages. CD8 T cells, on the other hand, are increased in number and cause lymphocytic alveolitis. Specific antibody responses by B-lymphocytes are decreased and opsonization of microorganisms is impaired. These observed defects in host defense of the respiratory tract explain the susceptibility of HIV-infected persons for oropharyngeal candidiasis, bacterial pneumonia, Pneumocystis pneumonia, and other opportunistic infections. PMID:26974294

  1. Moscow's defense intellectuals

    SciTech Connect

    Lambeth, B.S.

    1990-01-01

    This essay was originally written two decades ago as a seminar paper. A substantial portion of it addresses what were then only the first steps toward the establishment of a community of professional civilian defense analysts in the Soviet Union. Throughout most of the intervening period, that community found itself mired in immobilism as jurisdiction over such key Soviet national security inputs as military doctrine, force requirements, resource needs, and to a considerable degree, arms negotiating positions remained an exclusive prerogative of the Defense Ministry and the General Staff. Today, this former military monopoly has come to be challenged with increasing success by a host of newcomers to the Soviet defense scene, including the Foreign Ministry, the Supreme Soviet, and an ambitious cadre of civilian analysts attached to the social science research institutes of the Academy of Sciences. These individuals are making a determined bid for greater influence over Soviet defense policy, with the express encouragement of President Gorbachev and his supporters. The result has been an unprecedented infusion of pluralism into Soviet defense politics and a significant change in the content and goals of Soviet military policy.

  2. Early hematopoiesis and macrophage development.

    PubMed

    McGrath, Kathleen E; Frame, Jenna M; Palis, James

    2015-12-01

    The paradigm that all blood cells are derived from hematopoietic stem cells (HSCs) has been challenged by two findings. First, there are tissue-resident hematopoietic cells, including subsets of macrophages that are not replenished by adult HSCs, but instead are maintained by self-renewal of fetal-derived cells. Second, during embryogenesis, there is a conserved program of HSC-independent hematopoiesis that precedes HSC function and is required for embryonic survival. The presence of waves of HSC-independent hematopoiesis as well as fetal HSCs raises questions about the origin of fetal-derived adult tissue-resident macrophages. In the murine embryo, historical examination of embryonic macrophage and monocyte populations combined with recent reports utilizing genetic lineage-tracing approaches has led to a model of macrophage ontogeny that can be integrated with existing models of hematopoietic ontogeny. The first wave of hematopoiesis contains primitive erythroid, megakaryocyte and macrophage progenitors that arise in the yolk sac, and these macrophage progenitors are the source of early macrophages throughout the embryo, including the liver. A second wave of multipotential erythro-myeloid progenitors (EMPs) also arises in the yolk sac. EMPs colonize the fetal liver, initiating myelopoiesis and forming macrophages. Lineage tracing indicates that this second wave of macrophages are distributed in most fetal tissues, although not appreciably in the brain. Thus, fetal-derived adult tissue-resident macrophages, other than microglia, appear to predominately derive from EMPs. While HSCs emerge at midgestation and colonize the fetal liver, the relative contribution of fetal HSCs to tissue macrophages at later stages of development is unclear. The inclusion of macrophage potential in multiple waves of hematopoiesis is consistent with reports of their functional roles throughout development in innate immunity, phagocytosis, and tissue morphogenesis and remodeling

  3. Imaging macrophages with nanoparticles

    NASA Astrophysics Data System (ADS)

    Weissleder, Ralph; Nahrendorf, Matthias; Pittet, Mikael J.

    2014-02-01

    Nanomaterials have much to offer, not only in deciphering innate immune cell biology and tracking cells, but also in advancing personalized clinical care by providing diagnostic and prognostic information, quantifying treatment efficacy and designing better therapeutics. This Review presents different types of nanomaterial, their biological properties and their applications for imaging macrophages in human diseases, including cancer, atherosclerosis, myocardial infarction, aortic aneurysm, diabetes and other conditions. We anticipate that future needs will include the development of nanomaterials that are specific for immune cell subsets and can be used as imaging surrogates for nanotherapeutics. New in vivo imaging clinical tools for noninvasive macrophage quantification are thus ultimately expected to become relevant to predicting patients' clinical outcome, defining treatment options and monitoring responses to therapy.

  4. Tissue-resident macrophage enhancer landscapes are shaped by the local microenvironment.

    PubMed

    Lavin, Yonit; Winter, Deborah; Blecher-Gonen, Ronnie; David, Eyal; Keren-Shaul, Hadas; Merad, Miriam; Jung, Steffen; Amit, Ido

    2014-12-01

    Macrophages are critical for innate immune defense and also control organ homeostasis in a tissue-specific manner. They provide a fitting model to study the impact of ontogeny and microenvironment on chromatin state and whether chromatin modifications contribute to macrophage identity. Here, we profile the dynamics of four histone modifications across seven tissue-resident macrophage populations. We identify 12,743 macrophage-specific enhancers and establish that tissue-resident macrophages have distinct enhancer landscapes beyond what can be explained by developmental origin. Combining our enhancer catalog with gene expression profiles and open chromatin regions, we show that a combination of tissue- and lineage-specific transcription factors form the regulatory networks controlling chromatin specification in tissue-resident macrophages. The environment is capable of shaping the chromatin landscape of transplanted bone marrow precursors, and even differentiated macrophages can be reprogrammed when transferred into a new microenvironment. These results provide a comprehensive view of macrophage regulatory landscape and highlight the importance of the microenvironment, along with pioneer factors in orchestrating identity and plasticity. PMID:25480296

  5. Hypoxia and classical activation limits Mycobacterium tuberculosis survival by Akt-dependent glycolytic shift in macrophages

    PubMed Central

    Matta, S K; Kumar, D

    2016-01-01

    Cellular reactive oxygen species (ROS) is a major antibacterial defense mechanism used by macrophages upon activation. Exposure of Mycobacterium tuberculosis (Mtb)-infected macrophages to hypoxia is known to compromise the survival of the pathogen. Here we report that the hypoxia-induced control of intracellular Mtb load in RAW 264.7 macrophages was mediated by regulating the cellular ROS levels. We show that similar to classical activation, hypoxia incubation of macrophages resulted in decreased mitochondrial outer membrane potential (MOMP) and a concomitant increase in the cellular ROS levels. Mitochondrial depolarization and consequently higher ROS could be blocked by knocking down Akt using siRNAs, which acted by inhibiting the switch to glycolytic mode of metabolism, an essential adaptive response upon classical activation or hypoxic incubation of macrophages. Moreover, in the classically activated macrophages or in the macrophages under hypoxia incubation, supplementation with additional glucose had similar effects as Akt knockdown. Interestingly, in both the cases, the reversal of phenotype was linked with the ability of the mitochondrial F0–F1 ATP synthase activity to maintain the MOMP in the absence of oxidative phosphorylation. Both Akt knockdown and glucose supplementation were also able to rescue Mtb survival in these macrophages upon classical activation or hypoxia incubation. These results provide a framework for better understanding of how the interplay between oxygen supply, which is limiting in the human tubercular granulomas, and nutrient availability could together direct the outcome of infections in vivo. PMID:27551515

  6. Value of space defenses

    SciTech Connect

    Canavan, G.H.

    1992-10-29

    This report discusses the economic value of defenses against Near-Earth Object (NEO) impacts is bounded by calculating expected losses in their absence, which illustrates the contributions from NEOs of different sizes and the sensitivity of total expected losses to impact frequencies. For typical size distributions and damage of only a few decades duration, losses are most sensitive to small NEOs, and lead to defenses worth a few $M/yr. When the persistence of damage with NEO size is taken into account, that shifts the loss to the largest NEOs and greatly increases expected loss and values.

  7. Macrophage immunoregulatory pathways in tuberculosis

    PubMed Central

    Rajaram, Murugesan V.S.; Ni, Bin; Dodd, Claire E.; Schlesinger, Larry S.

    2014-01-01

    Macrophages, the major host cells harboring Mycobacterium tuberculosis (M.tb), are a heterogeneous cell type depending on their tissue of origin and host they are derived from. Significant discord in macrophage responses to M.tb exists due to differences in M.tb strains and the various types of macrophages used to study tuberculosis (TB). This review will summarize current concepts regarding macrophage responses to M.tb infection, while pointing out relevant differences in experimental outcomes due to the use of divergent model systems. A brief description of the lung environment is included since there is increasing evidence that the alveolar macrophage (AM) has immunoregulatory properties that can delay optimal protective host immune responses. In this context, this review focuses on selected macrophage immunoregulatory pattern recognition receptors (PRRs), cytokines, negative regulators of inflammation, lipid mediators and microRNAs (miRNAs). PMID:25453226

  8. The macrophages in rheumatic diseases

    PubMed Central

    Laria, Antonella; Lurati, Alfredomaria; Marrazza, Mariagrazia; Mazzocchi, Daniela; Re, Katia Angela; Scarpellini, Magda

    2016-01-01

    Macrophages belong to the innate immune system giving us protection against pathogens. However it is known that they are also involved in rheumatic diseases. Activated macrophages have two different phenotypes related to different stimuli: M1 (classically activated) and M2 (alternatively activated). M1 macrophages release high levels of pro-inflammatory cytokines, reactive nitrogen and oxygen intermediates killing microorganisms and tumor cells; while M2 macrophages are involved in resolution of inflammation through phagocytosis of apoptotic neutrophils, reduced production of pro-inflammatory cytokines, and increased synthesis of mediators important in tissue remodeling, angiogenesis, and wound repair. The role of macrophages in the different rheumatic diseases is different according to their M1/M2 macrophages phenotype. PMID:26929657

  9. Loa loa Microfilariae evade complement attack in vivo by acquiring regulatory proteins from host plasma.

    PubMed

    Haapasalo, Karita; Meri, Taru; Jokiranta, T Sakari

    2009-09-01

    Loa loa is a filarial nematode that infects humans. The adults live in subcutaneous tissues and produce microfilariae that live for several weeks in the blood circulation in order to be transmitted to another person via blood meals of a dipterian vector. As microfilariae live in continuous contact with plasma, it is obvious that they evade the complement system. We studied markers of complement activation and signs of complement regulation on Loa loa microfilariae in vivo. The microfilariae were isolated from anticoagulated blood samples of a Loa loa-infected Caucasian patient. C1q and some mannose-binding lectin but only a limited amount of C3b or C4b fragments and practically no C5 or C5b-9 were present on the microfilariae. The covalently microfilaria-bound C3 and C4 depositions were mainly inactive iC3b, C3c, and iC4b fragments indicating that microfilariae had regulated complement activation in vivo. Also, in vitro deposition of C3b onto the microfilariae upon serum exposure was limited. The patient-isolated microfilariae were found to carry the host complement regulators factor H and C4b-binding protein on the outermost layer, so called sheath. The microfilaria-bound factor H was functionally active. Binding of the complement regulators to the microfilariae was confirmed in vitro using (125)I-labeled factor H and C4b-binding protein. In conclusion, our study shows that Loa loa microfilariae block complement activation and acquire the host complement regulators factor H and C4b-binding protein in blood circulation. This is the first time that binding of complement regulators onto nonviral pathogens has been demonstrated to occur in humans in vivo. PMID:19528206

  10. Plasmodium falciparum evades mosquito immunity by disrupting JNK-mediated apoptosis of invaded midgut cells.

    PubMed

    Ramphul, Urvashi N; Garver, Lindsey S; Molina-Cruz, Alvaro; Canepa, Gaspar E; Barillas-Mury, Carolina

    2015-02-01

    The malaria parasite, Plasmodium, must survive and develop in the mosquito vector to be successfully transmitted to a new host. The Plasmodium falciparum Pfs47 gene is critical for malaria transmission. Parasites that express Pfs47 (NF54 WT) evade mosquito immunity and survive, whereas Pfs47 knockouts (KO) are efficiently eliminated by the complement-like system. Two alternative approaches were used to investigate the mechanism of action of Pfs47 on immune evasion. First, we examined whether Pfs47 affected signal transduction pathways mediating mosquito immune responses, and show that the Jun-N-terminal kinase (JNK) pathway is a key mediator of Anopheles gambiae antiplasmodial responses to P. falciparum infection and that Pfs47 disrupts JNK signaling. Second, we used microarrays to compare the global transcriptional responses of A. gambiae midguts to infection with WT and KO parasites. The presence of Pfs47 results in broad and profound changes in gene expression in response to infection that are already evident 12 h postfeeding, but become most prominent at 26 h postfeeding, the time when ookinetes invade the mosquito midgut. Silencing of 15 differentially expressed candidate genes identified caspase-S2 as a key effector of Plasmodium elimination in parasites lacking Pfs47. We provide experimental evidence that JNK pathway regulates activation of caspases in Plasmodium-invaded midgut cells, and that caspase activation is required to trigger midgut epithelial nitration. Pfs47 alters the cell death pathway of invaded midgut cells by disrupting JNK signaling and prevents the activation of several caspases, resulting in an ineffective nitration response that makes the parasite undetectable by the mosquito complement-like system. PMID:25552553

  11. Plasmodium falciparum evades mosquito immunity by disrupting JNK-mediated apoptosis of invaded midgut cells

    PubMed Central

    Ramphul, Urvashi N.; Garver, Lindsey S.; Molina-Cruz, Alvaro; Canepa, Gaspar E.; Barillas-Mury, Carolina

    2015-01-01

    The malaria parasite, Plasmodium, must survive and develop in the mosquito vector to be successfully transmitted to a new host. The Plasmodium falciparum Pfs47 gene is critical for malaria transmission. Parasites that express Pfs47 (NF54 WT) evade mosquito immunity and survive, whereas Pfs47 knockouts (KO) are efficiently eliminated by the complement-like system. Two alternative approaches were used to investigate the mechanism of action of Pfs47 on immune evasion. First, we examined whether Pfs47 affected signal transduction pathways mediating mosquito immune responses, and show that the Jun-N-terminal kinase (JNK) pathway is a key mediator of Anopheles gambiae antiplasmodial responses to P. falciparum infection and that Pfs47 disrupts JNK signaling. Second, we used microarrays to compare the global transcriptional responses of A. gambiae midguts to infection with WT and KO parasites. The presence of Pfs47 results in broad and profound changes in gene expression in response to infection that are already evident 12 h postfeeding, but become most prominent at 26 h postfeeding, the time when ookinetes invade the mosquito midgut. Silencing of 15 differentially expressed candidate genes identified caspase-S2 as a key effector of Plasmodium elimination in parasites lacking Pfs47. We provide experimental evidence that JNK pathway regulates activation of caspases in Plasmodium-invaded midgut cells, and that caspase activation is required to trigger midgut epithelial nitration. Pfs47 alters the cell death pathway of invaded midgut cells by disrupting JNK signaling and prevents the activation of several caspases, resulting in an ineffective nitration response that makes the parasite undetectable by the mosquito complement-like system. PMID:25552553

  12. EFFECTS OF INHALATION OF ETHYLENE DICHLORIDE ON PULMONARY DEFENSES OF MICE AND RATS

    EPA Science Inventory

    The effects of single or multiple 3-hr inhalation exposures to ethylene dichloride (dichloroethane or DCE) on macrophage functions and pulmonary defense were evaluated. Single exposures to the TLV level of DCE (10 ppm) resulted in decreased pulmonary bactericidal activity and inc...

  13. Th2 cytokine-induced alterations in intestinal smooth muscle function depend on alternatively activated macrophages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enteric nematode infection induces a strong Th2 cytokine response and is characterized by increased infiltration of various immune cells including macrophages. The role of these immune cells in host defense against enteric nematode infection, however, remains poorly defined. The present study invest...

  14. MODULATION OF HUMAN ALVEOLAR MACROPHAGE PROPERTIES BY OZONE EXPOSURE IN VITRO

    EPA Science Inventory

    We have investigated changes in human alveolar macrophage (HAM) function after exposure in vitro to ozone (O3) (0.1-1.0 ppm for 2-4 hours). he functions studied reflect concern that 03 is detrimental to host defense mechanisms in the broncho-alveolar spaces. xposure of HAM to cau...

  15. Distinct immunoregulatory properties of macrophage migration inhibitory factors encoded by Eimeria parasites and their chicken host

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays an important role in host defense against a variety of microorganisms including protozoan parasites. Interestingly, some microbial pathogens also express a MIF-like protein, although its role in disease pathogenesi...

  16. Macrophages in homeostatic immune function.

    PubMed

    Jantsch, Jonathan; Binger, Katrina J; Müller, Dominik N; Titze, Jens

    2014-01-01

    Macrophages are not only involved in inflammatory and anti-infective processes, but also play an important role in maintaining tissue homeostasis. In this review, we summarize recent evidence investigating the role of macrophages in controlling angiogenesis, metabolism as well as salt and water balance. Particularly, we summarize the importance of macrophage tonicity enhancer binding protein (TonEBP, also termed nuclear factor of activated T-cells 5 [NFAT5]) expression in the regulation of salt and water homeostasis. Further understanding of homeostatic macrophage function may lead to new therapeutic approaches to treat ischemia, hypertension and metabolic disorders. PMID:24847274

  17. Bioelectric modulation of macrophage polarization

    NASA Astrophysics Data System (ADS)

    Li, Chunmei; Levin, Michael; Kaplan, David L.

    2016-02-01

    Macrophages play a critical role in regulating wound healing and tissue regeneration by changing their polarization state in response to local microenvironmental stimuli. The native roles of polarized macrophages encompass biomaterials and tissue remodeling needs, yet harnessing or directing the polarization response has been largely absent as a potential strategy to exploit in regenerative medicine to date. Recent data have revealed that specific alteration of cells’ resting potential (Vmem) is a powerful tool to direct proliferation and differentiation in a number of complex tissues, such as limb regeneration, craniofacial patterning and tumorigenesis. In this study, we explored the bioelectric modulation of macrophage polarization by targeting ATP sensitive potassium channels (KATP). Glibenclamide (KATP blocker) and pinacidil (KATP opener) treatment not only affect macrophage polarization, but also influence the phenotype of prepolarized macrophages. Furthermore, modulation of cell membrane electrical properties can fine-tune macrophage plasticity. Glibenclamide decreased the secretion and gene expression of selected M1 markers, while pinacidil augmented M1 markers. More interestingly, glibencalmide promoted macrophage alternative activation by enhancing certain M2 markers during M2 polarization. These findings suggest that control of bioelectric properties of macrophages could offer a promising approach to regulate macrophage phenotype as a useful tool in regenerative medicine.

  18. Macrophages in homeostatic immune function

    PubMed Central

    Jantsch, Jonathan; Binger, Katrina J.; Müller, Dominik N.; Titze, Jens

    2014-01-01

    Macrophages are not only involved in inflammatory and anti-infective processes, but also play an important role in maintaining tissue homeostasis. In this review, we summarize recent evidence investigating the role of macrophages in controlling angiogenesis, metabolism as well as salt and water balance. Particularly, we summarize the importance of macrophage tonicity enhancer binding protein (TonEBP, also termed nuclear factor of activated T-cells 5 [NFAT5]) expression in the regulation of salt and water homeostasis. Further understanding of homeostatic macrophage function may lead to new therapeutic approaches to treat ischemia, hypertension and metabolic disorders. PMID:24847274

  19. Bioelectric modulation of macrophage polarization

    PubMed Central

    Li, Chunmei; Levin, Michael; Kaplan, David L.

    2016-01-01

    Macrophages play a critical role in regulating wound healing and tissue regeneration by changing their polarization state in response to local microenvironmental stimuli. The native roles of polarized macrophages encompass biomaterials and tissue remodeling needs, yet harnessing or directing the polarization response has been largely absent as a potential strategy to exploit in regenerative medicine to date. Recent data have revealed that specific alteration of cells’ resting potential (Vmem) is a powerful tool to direct proliferation and differentiation in a number of complex tissues, such as limb regeneration, craniofacial patterning and tumorigenesis. In this study, we explored the bioelectric modulation of macrophage polarization by targeting ATP sensitive potassium channels (KATP). Glibenclamide (KATP blocker) and pinacidil (KATP opener) treatment not only affect macrophage polarization, but also influence the phenotype of prepolarized macrophages. Furthermore, modulation of cell membrane electrical properties can fine-tune macrophage plasticity. Glibenclamide decreased the secretion and gene expression of selected M1 markers, while pinacidil augmented M1 markers. More interestingly, glibencalmide promoted macrophage alternative activation by enhancing certain M2 markers during M2 polarization. These findings suggest that control of bioelectric properties of macrophages could offer a promising approach to regulate macrophage phenotype as a useful tool in regenerative medicine. PMID:26869018

  20. Bioelectric modulation of macrophage polarization.

    PubMed

    Li, Chunmei; Levin, Michael; Kaplan, David L

    2016-01-01

    Macrophages play a critical role in regulating wound healing and tissue regeneration by changing their polarization state in response to local microenvironmental stimuli. The native roles of polarized macrophages encompass biomaterials and tissue remodeling needs, yet harnessing or directing the polarization response has been largely absent as a potential strategy to exploit in regenerative medicine to date. Recent data have revealed that specific alteration of cells' resting potential (Vmem) is a powerful tool to direct proliferation and differentiation in a number of complex tissues, such as limb regeneration, craniofacial patterning and tumorigenesis. In this study, we explored the bioelectric modulation of macrophage polarization by targeting ATP sensitive potassium channels (KATP). Glibenclamide (KATP blocker) and pinacidil (KATP opener) treatment not only affect macrophage polarization, but also influence the phenotype of prepolarized macrophages. Furthermore, modulation of cell membrane electrical properties can fine-tune macrophage plasticity. Glibenclamide decreased the secretion and gene expression of selected M1 markers, while pinacidil augmented M1 markers. More interestingly, glibencalmide promoted macrophage alternative activation by enhancing certain M2 markers during M2 polarization. These findings suggest that control of bioelectric properties of macrophages could offer a promising approach to regulate macrophage phenotype as a useful tool in regenerative medicine. PMID:26869018

  1. 75 FR 76423 - Defense Intelligence Agency National Defense Intelligence College Board of Visitors Closed Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-08

    ... of the Secretary Defense Intelligence Agency National Defense Intelligence College Board of Visitors Closed Meeting AGENCY: National Defense Intelligence College, Defense Intelligence Agency, Department of... a closed meeting of the Defense Intelligence Agency National Defense Intelligence College Board...

  2. 76 FR 28960 - Defense Intelligence Agency National Defense Intelligence College Board of Visitors Closed Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-19

    ... of the Secretary Defense Intelligence Agency National Defense Intelligence College Board of Visitors Closed Meeting AGENCY: National Defense Intelligence College, Defense Intelligence Agency, Department of... a closed meeting of the Defense Intelligence Agency National Defense Intelligence College Board...

  3. 76 FR 28757 - Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-18

    ... of the Secretary Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense Logistics Agency Actions AGENCY: Defense Logistics Agency, Department of Defense. ACTION: Notice of Availability (NOA) of Revised Defense Logistics Agency Regulation. SUMMARY: The Defense...

  4. Radiological Defense Manual.

    ERIC Educational Resources Information Center

    Defense Civil Preparedness Agency (DOD), Washington, DC.

    Originally prepared for use as a student textbook in Radiological Defense (RADEF) courses, this manual provides the basic technical information necessary for an understanding of RADEF. It also briefly discusses the need for RADEF planning and expected postattack emergency operations. There are 14 chapters covering these major topics: introduction…

  5. Censorship: Tactics for Defense.

    ERIC Educational Resources Information Center

    Lowery, Skip

    1998-01-01

    Book banners are generally successful because they have a wide network of support, including national coalitions with sophisticated organizational methods--such as electing certain people to school boards. School officials should get organized and devise defensive strategies, such as inviting critics to class, asking what they would like to…

  6. Defense Language Institute.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    Discussed in this Defense Language Institute (DLI) brochure are its intensive language programs' history, and its four schools, which are located in Monterey, California, Washington, D.C., Lackland Air Force Base, and Fort Bliss, Texas. Proficiency levels determined by the DLI and utilization of the audiolingual method are also described.…

  7. Protective roles of free avian respiratory macrophages in captive birds.

    PubMed

    Mutua, Mbuvi P; Muya, Shadrack; Gicheru, Muita M

    2016-01-01

    In the mammalian lung, respiratory macrophages provide front line defense against invading pathogens and particulate matter. In birds, respiratory macrophages are known as free avian respiratory macrophages (FARM) and a dearth of the cells in the avian lung has been purported to foreordain a weak first line of pulmonary defense, a condition associated with high mortality of domestic birds occasioned by respiratory inflictions. Avian pulmonary mechanisms including a three tiered aerodynamic filtration system, tight epithelial junctions and an efficient mucociliary escalator system have been known to supplement FARM protective roles. Current studies, however, report FARM to exhibit an exceptionally efficient phagocytic capacity and are effective in elimination of invading pathogens. In this review, we also report on effects of selective synthetic peroxisome proliferator activated receptor gamma (PPAR γ) agonists on non phlogistic phagocytic properties in the FARM. To develop effective therapeutic interventions targeting FARM in treatment and management of respiratory disease conditions in the poultry, further studies are required to fully understand the role of FARM in innate and adaptive immune responses. PMID:27306902

  8. Defense styles of pedophilic offenders.

    PubMed

    Drapeau, Martin; Beretta, Véronique; de Roten, Yves; Koerner, Annett; Despland, Jean-Nicolas

    2008-04-01

    This pilot study investigated the defense styles of pedophile sexual offenders. Interviews with 20 pedophiles and 20 controls were scored using the Defense Mechanisms Rating Scales. Results showed that pedophiles had a significantly lower overall defensive functioning score than the controls. Pedophiles used significantly fewer obsessional-level defenses but more major image-distorting and action-level defenses. Results also suggested differences in the prevalence of individual defenses where pedophiles used more dissociation, displacement, denial, autistic fantasy, splitting of object, projective identification, acting out, and passive aggressive behavior but less intellectualization and rationalization. PMID:17875603

  9. 9. BASRELIEF DECORATION, 'DEFENSE', MURAL COMMEMORATING THE DEFENSE OF FORT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. BAS-RELIEF DECORATION, 'DEFENSE', MURAL COMMEMORATING THE DEFENSE OF FORT DEARBORN - Chicago River Bascule Bridge, Michigan Avenue, Spanning Chicago River at North Michigan Avenue, Chicago, Cook County, IL

  10. Macrophages in Collateral Arteriogenesis

    PubMed Central

    Fung, Erik; Helisch, Armin

    2012-01-01

    Arteriosclerotic vascular disease is the most common cause of death and a major cause of disability in the developed world. Adverse outcomes of arteriosclerotic vascular disease are related to consequences of tissue ischemia and necrosis affecting the heart, brain, limbs, and other organs. Collateral artery growth or arteriogenesis occurs naturally and can help restore perfusion to ischemic tissues. Understanding the mechanisms of collateral artery growth may provide therapeutic options for patients with ischemic vascular disease. In this review, we examine the evidence for a role of monocytes and macrophages in collateral arteriogenesis. PMID:23055975

  11. Leukotriene B4 enhances innate immune defense against the puerperal sepsis agent Streptococcus pyogenes.

    PubMed

    Soares, Elyara M; Mason, Katie L; Rogers, Lisa M; Serezani, Carlos H; Faccioli, Lucia H; Aronoff, David M

    2013-02-15

    Puerperal sepsis is a leading cause of maternal mortality worldwide. Streptococcus pyogenes [group A Streptococcus; (GAS)] is a major etiologic agent of severe postpartum sepsis, yet little is known regarding the pathogenesis of these infections. Tissue macrophages provide innate defense against GAS, and their actions are highly regulated. The intracellular second messenger cAMP can negatively regulate macrophage actions against GAS. Because leukotriene (LT) B(4) has been shown to suppress intracellular cAMP in macrophages, we hypothesized that it could enhance innate defenses against GAS. We assessed the capacity of LTB(4) to modulate antistreptococcal actions of human macrophages, including placental and decidual macrophages and used a novel intrauterine infection model of GAS in mice lacking the 5-lipoxygenase enzyme to determine the role of endogenous LTs in host defense against this pathogen. Animals lacking 5-lipoxygenase were significantly more vulnerable to intrauterine GAS infection than were wild-type mice and showed enhanced dissemination of bacteria out of the uterus and a more robust inflammatory response than did wild-type mice. In addition, LTB(4) reduced intracellular cAMP levels via the BLT1 receptor and was a potent stimulant of macrophage phagocytosis and NADPH oxidase-dependent intracellular killing of GAS. Importantly, interference was observed between the macrophage immunomodulatory actions of LTB(4) and the cAMP-inducing lipid PGE(2), suggesting that interplay between pro- and anti-inflammatory compounds may be important in vivo. This work underscores the potential for pharmacological targeting of lipid mediator signaling cascades in the treatment of invasive GAS infections. PMID:23325886

  12. Subterranean termite prophylactic secretions and external antifungal defenses.

    PubMed

    Hamilton, Casey; Lay, Frank; Bulmer, Mark S

    2011-09-01

    Termites exploit environments that make them susceptible to infection and rapid disease transmission. Gram-negative bacteria binding proteins (GNBPs) signal the presence of microbes and in some insects directly damage fungal pathogens with β-1,3-glucanase activity. The subterranean termites Reticulitermes flavipes and Reticulitermes virginicus encounter soil entomopathogenic fungi such as Metarhizium anisopliae, which can evade host immune responses after penetrating the cuticle. An external defense that prevents invasion of fungal pathogens could be crucial in termites, allowing them to thrive under high pathogenic pressures. We investigated the role of secreted β-1,3-glucanases in Reticulitermes defenses against M. anisopliae. Our results show that these termites secrete antifungal β-1,3-glucanases on the cuticle, and the specific inhibition of GNBP associated β-1,3-glucanase activity with d-δ-gluconolactone (GDL) reduces this activity and can cause significant increases in mortality after exposure to M. anisopliae. Secreted β-1,3-glucanases appear to be essential in preventing infection by breaking down fungi externally. PMID:21708164

  13. S100A12 Is Part of the Antimicrobial Network against Mycobacterium leprae in Human Macrophages

    PubMed Central

    Realegeno, Susan; Kelly-Scumpia, Kindra M.; Dang, Angeline Tilly; Lu, Jing; Teles, Rosane; Liu, Philip T.; Schenk, Mirjam; Schmidt, Nathan W.; Wong, Gerard C. L.; Sarno, Euzenir N.; Ochoa, Maria T.; Pellegrini, Matteo; Modlin, Robert L.

    2016-01-01

    Triggering antimicrobial mechanisms in macrophages infected with intracellular pathogens, such as mycobacteria, is critical to host defense against the infection. To uncover the unique and shared antimicrobial networks induced by the innate and adaptive immune systems, gene expression profiles generated by RNA sequencing (RNAseq) from human monocyte-derived macrophages (MDMs) activated with TLR2/1 ligand (TLR2/1L) or IFN-γ were analyzed. Weighed gene correlation network analysis identified modules of genes strongly correlated with TLR2/1L or IFN-γ that were linked by the “defense response” gene ontology term. The common TLR2/1L and IFN-γ inducible human macrophage host defense network contained 16 antimicrobial response genes, including S100A12, which was one of the most highly induced genes by TLR2/1L. There is limited information on the role of S100A12 in infectious disease, leading us to test the hypothesis that S100A12 contributes to host defense against mycobacterial infection in humans. We show that S100A12 is sufficient to directly kill Mycobacterium tuberculosis and Mycobacterium leprae. We also demonstrate that S100A12 is required for TLR2/1L and IFN-γ induced antimicrobial activity against M. leprae in infected macrophages. At the site of disease in leprosy, we found that S100A12 was more strongly expressed in skin lesions from tuberculoid leprosy (T-lep), the self-limiting form of the disease, compared to lepromatous leprosy (L-lep), the progressive form of the disease. These data suggest that S100A12 is part of an innate and adaptive inducible antimicrobial network that contributes to host defense against mycobacteria in infected macrophages. PMID:27355424

  14. S100A12 Is Part of the Antimicrobial Network against Mycobacterium leprae in Human Macrophages.

    PubMed

    Realegeno, Susan; Kelly-Scumpia, Kindra M; Dang, Angeline Tilly; Lu, Jing; Teles, Rosane; Liu, Philip T; Schenk, Mirjam; Lee, Ernest Y; Schmidt, Nathan W; Wong, Gerard C L; Sarno, Euzenir N; Rea, Thomas H; Ochoa, Maria T; Pellegrini, Matteo; Modlin, Robert L

    2016-06-01

    Triggering antimicrobial mechanisms in macrophages infected with intracellular pathogens, such as mycobacteria, is critical to host defense against the infection. To uncover the unique and shared antimicrobial networks induced by the innate and adaptive immune systems, gene expression profiles generated by RNA sequencing (RNAseq) from human monocyte-derived macrophages (MDMs) activated with TLR2/1 ligand (TLR2/1L) or IFN-γ were analyzed. Weighed gene correlation network analysis identified modules of genes strongly correlated with TLR2/1L or IFN-γ that were linked by the "defense response" gene ontology term. The common TLR2/1L and IFN-γ inducible human macrophage host defense network contained 16 antimicrobial response genes, including S100A12, which was one of the most highly induced genes by TLR2/1L. There is limited information on the role of S100A12 in infectious disease, leading us to test the hypothesis that S100A12 contributes to host defense against mycobacterial infection in humans. We show that S100A12 is sufficient to directly kill Mycobacterium tuberculosis and Mycobacterium leprae. We also demonstrate that S100A12 is required for TLR2/1L and IFN-γ induced antimicrobial activity against M. leprae in infected macrophages. At the site of disease in leprosy, we found that S100A12 was more strongly expressed in skin lesions from tuberculoid leprosy (T-lep), the self-limiting form of the disease, compared to lepromatous leprosy (L-lep), the progressive form of the disease. These data suggest that S100A12 is part of an innate and adaptive inducible antimicrobial network that contributes to host defense against mycobacteria in infected macrophages. PMID:27355424

  15. Phosphatase regulation of macrophage activation.

    PubMed

    Kozicky, Lisa K; Sly, Laura M

    2015-08-01

    Macrophages are innate immune cells that play critical roles in tissue homeostasis and the immune response to invading pathogens or tumor cells. A hallmark of macrophages is their "plasticity," that is, their ability to respond to cues in their local microenvironment and adapt their activation state or phenotype to mount an appropriate response. During the inflammatory response, macrophages may be required to mount a profound anti-bacterial or anti-tumor response, an anti-inflammatory response, an anti-parasitic response, or a wound healing response. To do so, macrophages express cell surface receptors for growth factors, chemokines and cytokines, as well pathogen and danger associated molecular patterns. Downstream of these cell surface receptors, cell signalling cascades are activated and deactivated by reversible and competing activities of lipid and protein kinases and phosphatases. While kinases drive the activation of cell signalling pathways critical for macrophage activation, the strength and duration of the signalling is regulated by phosphatases. Hence, gene knockout mouse models have revealed critical roles for lipid and protein phosphatases in macrophage activation. Herein, we describe our current understanding and the key roles of specific cellular phosphatases in the regulation of the quality of macrophage polarization as well as the quantity of cytokines produced by activated macrophages. PMID:26216598

  16. Intracellular survival of Candida glabrata in macrophages: immune evasion and persistence.

    PubMed

    Kasper, Lydia; Seider, Katja; Hube, Bernhard

    2015-08-01

    Candida glabrata is a successful human opportunistic pathogen which causes superficial but also life-threatening systemic infections. During infection, C. glabrata has to cope with cells of the innate immune system such as macrophages, which belong to the first line of defense against invading pathogens. Candida glabrata is able to survive and even replicate inside macrophages while causing surprisingly low damage and cytokine release. Here, we present an overview of recent studies dealing with the interaction of C. glabrata with macrophages, from phagocytosis to intracellular growth and escape. We review the strategies of C. glabrata that permit intracellular survival and replication, including poor host cell activation, modification of phagosome maturation and phagosome pH, adaptation to antimicrobial activities, and mechanisms to overcome the nutrient limitations within the phagosome. In summary, these studies suggest that survival within macrophages may be an immune evasion and persistence strategy of C. glabrata during infection. PMID:26066553

  17. A fungal anticodon nuclease ribotoxin exploits a secondary cleavage site to evade tRNA repair.

    PubMed

    Meineke, Birthe; Kast, Alene; Schwer, Beate; Meinhardt, Friedhelm; Shuman, Stewart; Klassen, Roland

    2012-09-01

    PaOrf2 and γ-toxin subunits of Pichia acaciae toxin (PaT) and Kluyveromyces lactis zymocin are tRNA anticodon nucleases. These secreted ribotoxins are assimilated by Saccharomyces cerevisiae, wherein they arrest growth by depleting specific tRNAs. Toxicity can be recapitulated by induced intracellular expression of PaOrf2 or γ-toxin in S. cerevisiae. Mutational analysis of γ-toxin has identified amino acids required for ribotoxicity in vivo and RNA transesterification in vitro. Here, we report that PaOrf2 residues Glu9 and His287 (putative counterparts of γ-toxin Glu9 and His209) are essential for toxicity. Our results suggest a similar basis for RNA transesterification by PaOrf2 and γ-toxin, despite their dissimilar primary structures and distinctive tRNA target specificities. PaOrf2 makes two sequential incisions in tRNA, the first of which occurs 3' from the mcm(5)s(2)U wobble nucleoside and depends on mcm(5). A second incision two nucleotides upstream results in the net excision of a di-nucleotide. Expression of phage and plant tRNA repair systems can relieve PaOrf2 toxicity when tRNA cleavage is restricted to the secondary site in elp3 cells that lack the mcm(5) wobble U modification. Whereas the endogenous yeast tRNA ligase Trl1 can heal tRNA halves produced by PaOrf2 cleavage in elp3 cells, its RNA sealing activity is inadequate to complete the repair. Compatible sealing activity can be provided in trans by plant tRNA ligase. The damage-rescuing ability of tRNA repair systems is lost when PaOrf2 can break tRNA at both sites. These results highlight the logic of a two-incision mechanism of tRNA anticodon damage that evades productive repair by tRNA ligases. PMID:22836353

  18. Diverse macrophage populations mediate acute lung inflammation and resolution

    PubMed Central

    King, Landon S.; D'Alessio, Franco R.

    2014-01-01

    Acute respiratory distress syndrome (ARDS) is a devastating disease with distinct pathological stages. Fundamental to ARDS is the acute onset of lung inflammation as a part of the body's immune response to a variety of local and systemic stimuli. In patients surviving the inflammatory and subsequent fibroproliferative stages, transition from injury to resolution and recovery is an active process dependent on a series of highly coordinated events regulated by the immune system. Experimental animal models of acute lung injury (ALI) reproduce key components of the injury and resolution phases of human ARDS and provide a methodology to explore mechanisms and potential new therapies. Macrophages are essential to innate immunity and host defense, playing a featured role in the lung and alveolar space. Key aspects of their biological response, including differentiation, phenotype, function, and cellular interactions, are determined in large part by the presence, severity, and chronicity of local inflammation. Studies support the importance of macrophages to initiate and maintain the inflammatory response, as well as a determinant of resolution of lung inflammation and repair. We will discuss distinct roles for lung macrophages during early inflammatory and late resolution phases of ARDS using experimental animal models. In addition, each section will highlight human studies that relate to the diverse role of macrophages in initiation and resolution of ALI and ARDS. PMID:24508730

  19. [Thoughts on "defensive" medicine].

    PubMed

    Csiba, László

    2007-03-25

    "Defensive" medicine is called medical behaviour characterized by deformation of diagnostic and therapeutic activities due to fears endangering existence and work, thus some interventions are omitted or, on the contrary, superfluous examinations are proposed on account of internal uncertainty, the patient's distrust or hostile social environment. Trust relation between patient and physician is the most gravely damaged because of aggravation and distortion of some conscienceless physicians' abuses by the media; patient-physician relations may not be degraded to contractual legal relations. Young physicians must get acquainted with the joy of success in diagnostics that enriches the personality. They shall have healthy self-esteem and be ready to take diagnostic and therapeutic challenges on themselves. All of us have to fight against social atmosphere hostile to physicians, against causes inducing and augmenting practice of defensive medicine. PMID:17444017

  20. Defense Waste Processing Facility

    SciTech Connect

    Haselow, J.S.; Wilhite, E.L.; Stieve, A.L.

    1990-05-01

    The information contained in this report is intended to supplement the original Environmental Impact Statement (EIS) for the Defense Waste Processing Facility (DWPF). Since the original EIS in 1982, alterations have been made to he conceptual process that reduce the impact to the groundwater. This reduced impact is documented in this report along with an update of the understanding of seismology and geology of the Savannah River Site. 6 refs., 2 figs., 2 tabs.

  1. Rat lung macrophage tumor cytotoxin production: impairment by chronic in vivo cigarette smoke exposure.

    PubMed

    Flick, D A; Gonzalez-Rothi, R J; Harris, J O; Gifford, G E

    1985-11-01

    macrophage-mediated tumor defense mechanisms. PMID:2413988

  2. PE_PGRS30 of Mycobacterium tuberculosis mediates suppression of proinflammatory immune response in macrophages through its PGRS and PE domains.

    PubMed

    Chatrath, Shweta; Gupta, Vineet Kumar; Dixit, Aparna; Garg, Lalit C

    2016-09-01

    The success of Mycobacterium tuberculosis as a pathogen relies on its ability to survive inside macrophages and evade host immune mechanisms. M. tuberculosis employs multiple strategies to confer resistance against immune system including inhibition of phago-lysosomal fusion, modulation of cytokine responses and granuloma formation. PE_PGRS proteins, uniquely present in pathogenic mycobacteria, are cell surface molecules that are suggested to interact with host cells. PE_PGRS proteins have also been implicated in its pathogenesis. In the present study, immuno-regulatory property of Rv1651c-encoded PE_PGRS30 protein was explored. Infection of PMA-differentiated human THP-1 macrophages with Mycobacterium smegmatis harbouring pVV(1651c) resulted in reduced production of IL-12, TNF-α and IL-6, as compared to infection with M. smegmatis harbouring the control plasmid pVV16. No differential effect was observed on bacterial persistence inside macrophages or on macrophage mortality upon infection with the two recombinant strains. Infection of THP-1 macrophages with recombinant M. smegmatis expressing deletion variants of PE_PGRS30 indicated that anti-inflammatory function of the protein is possessed by its PGRS and PE domains while the C-terminal domain, when expressed alone, displayed antagonistic effect in terms of TNF-α secretion. These results suggest that PE_PGRS30 interferes with macrophage immune functions important for activation of adaptive T-cell responses. PMID:27129781

  3. 4T1 Murine Mammary Carcinoma Cells Enhance Macrophage-Mediated Innate Inflammatory Responses

    PubMed Central

    Madera, Laurence; Greenshields, Anna; Coombs, Melanie R. Power; Hoskin, David W.

    2015-01-01

    Tumor progression and the immune response are intricately linked. While it is known that cancers alter macrophage inflammatory responses to promote tumor progression, little is known regarding how cancers affect macrophage-dependent innate host defense. In this study, murine bone-marrow-derived macrophages (BMDM) were exposed to murine carcinoma-conditioned media prior to assessment of the macrophage inflammatory response. BMDMs exposed to 4T1 mammary carcinoma-conditioned medium demonstrated enhanced production of pro-inflammatory cytokines tumor necrosis factor α, interleukin-6, and CCL2 in response to lipopolysaccharide (LPS) while production of interleukin-10 remained unchanged. The increased LPS-induced production of pro-inflammatory cytokines was transient and correlated with enhanced cytokine production in response to other Toll-like receptor agonists, including peptidoglycan and flagellin. In addition, 4T1-conditioned BMDMs exhibited strengthened LPS-induced nitric oxide production and enhanced phagocytosis of Escherichia coli. 4T1-mediated augmentation of macrophage responses to LPS was partially dependent on the NFκB pathway, macrophage-colony stimulating factor, and actin polymerization, as well as the presence of 4T1-secreted extracellular vesicles. Furthermore, peritoneal macrophages obtained from 4T1 tumor-bearing mice displayed enhanced pro-inflammatory cytokine production in response to LPS. These results suggest that uptake of 4T1-secreted factors and actin-mediated ingestion of 4T1-secreted exosomes by macrophages cause a transient enhancement of innate inflammatory responses. Mammary carcinoma-mediated regulation of innate immunity may have significant implications for our understanding of host defense and cancer progression. PMID:26177198

  4. 4T1 Murine Mammary Carcinoma Cells Enhance Macrophage-Mediated Innate Inflammatory Responses.

    PubMed

    Madera, Laurence; Greenshields, Anna; Coombs, Melanie R Power; Hoskin, David W

    2015-01-01

    Tumor progression and the immune response are intricately linked. While it is known that cancers alter macrophage inflammatory responses to promote tumor progression, little is known regarding how cancers affect macrophage-dependent innate host defense. In this study, murine bone-marrow-derived macrophages (BMDM) were exposed to murine carcinoma-conditioned media prior to assessment of the macrophage inflammatory response. BMDMs exposed to 4T1 mammary carcinoma-conditioned medium demonstrated enhanced production of pro-inflammatory cytokines tumor necrosis factor α, interleukin-6, and CCL2 in response to lipopolysaccharide (LPS) while production of interleukin-10 remained unchanged. The increased LPS-induced production of pro-inflammatory cytokines was transient and correlated with enhanced cytokine production in response to other Toll-like receptor agonists, including peptidoglycan and flagellin. In addition, 4T1-conditioned BMDMs exhibited strengthened LPS-induced nitric oxide production and enhanced phagocytosis of Escherichia coli. 4T1-mediated augmentation of macrophage responses to LPS was partially dependent on the NFκB pathway, macrophage-colony stimulating factor, and actin polymerization, as well as the presence of 4T1-secreted extracellular vesicles. Furthermore, peritoneal macrophages obtained from 4T1 tumor-bearing mice displayed enhanced pro-inflammatory cytokine production in response to LPS. These results suggest that uptake of 4T1-secreted factors and actin-mediated ingestion of 4T1-secreted exosomes by macrophages cause a transient enhancement of innate inflammatory responses. Mammary carcinoma-mediated regulation of innate immunity may have significant implications for our understanding of host defense and cancer progression. PMID:26177198

  5. Expression of β-Defensin Genes in Bovine Alveolar Macrophages

    PubMed Central

    Ryan, Lisa K.; Rhodes, Janice; Bhat, Meenakshi; Diamond, Gill

    1998-01-01

    Bovine alveolar macrophages (BAM) were examined for the expression of β-defensins and to determine whether their expression could be upregulated by bacterial lipopolysaccharide (LPS), as observed with β-defensins expressed in bovine tracheal epithelial cells. Four β-defensins were expressed constitutively in BAM, with bovine neutrophil β-defensin (BNBD)-4 and BNBD-5 being the most predominant. This is the first evidence of β-defensin gene expression in a mature myeloid cell. LPS had no effect on β-defensin expression in BAM, even though tumor necrosis factor alpha (TNF-α) production was induced. Nonbacterial inflammatory particles had little effect on β-defensin gene expression or TNF-α production in BAM. We hypothesize that constitutively expressed β-defensins of alveolar macrophages may have a role in lung host defense. PMID:9453661

  6. Histone deacetylases in monocyte/macrophage development, activation and metabolism: refining HDAC targets for inflammatory and infectious diseases

    PubMed Central

    Das Gupta, Kaustav; Shakespear, Melanie R; Iyer, Abishek; Fairlie, David P; Sweet, Matthew J

    2016-01-01

    Macrophages have central roles in danger detection, inflammation and host defense, and consequently, these cells are intimately linked to most disease processes. Major advances in our understanding of the development and function of macrophages have recently come to light. For example, it is now clear that tissue-resident macrophages can be derived from either blood monocytes or through local proliferation of phagocytes that are originally seeded during embryonic development. Metabolic state has also emerged as a major control point for macrophage activation phenotypes. Herein, we review recent literature linking the histone deacetylase (HDAC) family of enzymes to macrophage development and activation, particularly in relation to these recent developments. There has been considerable interest in potential therapeutic applications for small molecule inhibitors of HDACs (HDACi), not only for cancer, but also for inflammatory and infectious diseases. However, the enormous range of molecular and cellular processes that are controlled by different HDAC enzymes presents a potential stumbling block to clinical development. We therefore present examples of how classical HDACs control macrophage functions, roles of specific HDACs in these processes and approaches for selective targeting of drugs, such as HDACi, to macrophages. Development of selective inhibitors of macrophage-expressed HDACs and/or selective delivery of pan HDACi to macrophages may provide avenues for enhancing efficacy of HDACi in therapeutic applications, while limiting unwanted side effects. PMID:26900475

  7. Defense on the Move: Ant-Based Cyber Defense

    SciTech Connect

    Fink, Glenn A.; Haack, Jereme N.; McKinnon, Archibald D.; Fulp, Errin W.

    2014-04-15

    Many common cyber defenses (like firewalls and IDS) are as static as trench warfare allowing the attacker freedom to probe them at will. The concept of Moving Target Defense (MTD) adds dynamism to the defender side, but puts the systems to be defended themselves in motion, potentially at great cost to the defender. An alternative approach is a mobile resilient defense that removes attackers’ ability to rely on prior experience without requiring motion in the protected infrastructure itself. The defensive technology absorbs most of the cost of motion, is resilient to attack, and is unpredictable to attackers. The Ant-Based Cyber Defense (ABCD) is a mobile resilient defense providing a set of roaming, bio-inspired, digital-ant agents working with stationary agents in a hierarchy headed by a human supervisor. The ABCD approach provides a resilient, extensible, and flexible defense that can scale to large, multi-enterprise infrastructures like the smart electric grid.

  8. Phagocytosis of Giardia muris by macrophages in Peyer's patch epithelium in mice.

    PubMed Central

    Owen, R L; Allen, C L; Stevens, D P

    1981-01-01

    No mechanism for the initiation of immunological clearance of Giardia from the mammalian intestinal tract has been identified. In normal and nude mice experimentally infected with G. muris, we examined antigen-sampling epithelium over Peyer's patch follicles by electron microscopy for evidence of interaction between G. muris and lymphoid cells. Invading G. muris were found in the epithelium near dying or desquamating columnar cells. Macrophages beneath the basal lamina extended pseudopods into the epithelium, trapping invading G. muris and enclosing them in phagolysosomes. In normal mice, which clear G. muris in 4 to 6 weeks, macrophages containing digested G. muris were surrounded by rosettes of lymphoblasts in the epithelium. In nude mice deficient in lymphocytes, there was apparent hyperplasia of macrophages, which filled the follicle domes, resulting in more frequent entrapment of G. muris but no contact between macrophages and lymphoblasts in the epithelium. In nude mice, which require 6 months to control G. muris infection, lymphoblast contact with macrophages containing distinctive microtubular remnants of G. muris was only identified in the follicle dome. This close physical association of lymphoblasts and macrophages containing G. muris remnants suggests that this macrophage activity represents intraepithelial antigen processing as well as a defense against the effects of the uncontrolled entrance of microorganisms and other antigenic particles into Peyer's patch lymphoid follicles. Images PMID:7275318

  9. TLR Stimulation Dynamically Regulates Heme and Iron Export Gene Expression in Macrophages.

    PubMed

    Philip, Mary; Chiu, Edison Y; Hajjar, Adeline M; Abkowitz, Janis L

    2016-01-01

    Pathogenic bacteria have evolved multiple mechanisms to capture iron or iron-containing heme from host tissues or blood. In response, organisms have developed defense mechanisms to keep iron from pathogens. Very little of the body's iron store is available as free heme; rather nearly all body iron is complexed with heme or other proteins. The feline leukemia virus, subgroup C (FeLV-C) receptor, FLVCR, exports heme from cells. It was unknown whether FLVCR regulates heme-iron availability after infection, but given that other heme regulatory proteins are upregulated in macrophages in response to bacterial infection, we hypothesized that macrophages dynamically regulate FLVCR. We stimulated murine primary macrophages or macrophage cell lines with LPS and found that Flvcr is rapidly downregulated in a TLR4/MD2-dependent manner; TLR1/2 and TLR3 stimulation also decreased Flvcr expression. We identified several candidate TLR-activated transcription factors that can bind to the Flvcr promoter. Macrophages must balance the need to sequester iron from systemic circulating or intracellular pathogens with the macrophage requirement for heme and iron to produce reactive oxygen species. Our findings underscore the complexity of this regulation and point to a new role for FLVCR and heme export in macrophages responses to infection and inflammation. PMID:27006955

  10. Activator of G-Protein Signaling 3-Induced Lysosomal Biogenesis Limits Macrophage Intracellular Bacterial Infection.

    PubMed

    Vural, Ali; Al-Khodor, Souhaila; Cheung, Gordon Y C; Shi, Chong-Shan; Srinivasan, Lalitha; McQuiston, Travis J; Hwang, Il-Young; Yeh, Anthony J; Blumer, Joe B; Briken, Volker; Williamson, Peter R; Otto, Michael; Fraser, Iain D C; Kehrl, John H

    2016-01-15

    Many intracellular pathogens cause disease by subverting macrophage innate immune defense mechanisms. Intracellular pathogens actively avoid delivery to or directly target lysosomes, the major intracellular degradative organelle. In this article, we demonstrate that activator of G-protein signaling 3 (AGS3), an LPS-inducible protein in macrophages, affects both lysosomal biogenesis and activity. AGS3 binds the Gi family of G proteins via its G-protein regulatory (GoLoco) motif, stabilizing the Gα subunit in its GDP-bound conformation. Elevated AGS3 levels in macrophages limited the activity of the mammalian target of rapamycin pathway, a sensor of cellular nutritional status. This triggered the nuclear translocation of transcription factor EB, a known activator of lysosomal gene transcription. In contrast, AGS3-deficient macrophages had increased mammalian target of rapamycin activity, reduced transcription factor EB activity, and a lower lysosomal mass. High levels of AGS3 in macrophages enhanced their resistance to infection by Burkholderia cenocepacia J2315, Mycobacterium tuberculosis, and methicillin-resistant Staphylococcus aureus, whereas AGS3-deficient macrophages were more susceptible. We conclude that LPS priming increases AGS3 levels, which enhances lysosomal function and increases the capacity of macrophages to eliminate intracellular pathogens. PMID:26667172

  11. Inflammation and ER Stress Downregulate BDH2 Expression and Dysregulate Intracellular Iron in Macrophages

    PubMed Central

    Zughaier, Susu M.; Stauffer, Brandon B.; McCarty, Nael A.

    2014-01-01

    Macrophages play a very important role in host defense and in iron homeostasis by engulfing senescent red blood cells and recycling iron. Hepcidin is the master iron regulating hormone that limits dietary iron absorption from the gut and limits iron egress from macrophages. Upon infection macrophages retain iron to limit its bioavailability which limits bacterial growth. Recently, a short chain butyrate dehydrogenase type 2 (BDH2) protein was reported to contain an iron responsive element and to mediate cellular iron trafficking by catalyzing the synthesis of the mammalian siderophore that binds labile iron; therefore, BDH2 plays a crucial role in intracellular iron homeostasis. However, BDH2 expression and regulation in macrophages have not yet been described. Here we show that LPS-induced inflammation combined with ER stress led to massive BDH2 downregulation, increased the expression of ER stress markers, upregulated hepcidin expression, downregulated ferroportin expression, caused iron retention in macrophages, and dysregulated cytokine release from macrophages. We also show that ER stress combined with inflammation synergistically upregulated the expression of the iron carrier protein NGAL and the stress-inducible heme degrading enzyme heme oxygenase-1 (HO-1) leading to iron liberation. This is the first report to show that inflammation and ER stress downregulate the expression of BDH2 in human THP-1 macrophages. PMID:25762501

  12. Inflammation and ER stress downregulate BDH2 expression and dysregulate intracellular iron in macrophages.

    PubMed

    Zughaier, Susu M; Stauffer, Brandon B; McCarty, Nael A

    2014-01-01

    Macrophages play a very important role in host defense and in iron homeostasis by engulfing senescent red blood cells and recycling iron. Hepcidin is the master iron regulating hormone that limits dietary iron absorption from the gut and limits iron egress from macrophages. Upon infection macrophages retain iron to limit its bioavailability which limits bacterial growth. Recently, a short chain butyrate dehydrogenase type 2 (BDH2) protein was reported to contain an iron responsive element and to mediate cellular iron trafficking by catalyzing the synthesis of the mammalian siderophore that binds labile iron; therefore, BDH2 plays a crucial role in intracellular iron homeostasis. However, BDH2 expression and regulation in macrophages have not yet been described. Here we show that LPS-induced inflammation combined with ER stress led to massive BDH2 downregulation, increased the expression of ER stress markers, upregulated hepcidin expression, downregulated ferroportin expression, caused iron retention in macrophages, and dysregulated cytokine release from macrophages. We also show that ER stress combined with inflammation synergistically upregulated the expression of the iron carrier protein NGAL and the stress-inducible heme degrading enzyme heme oxygenase-1 (HO-1) leading to iron liberation. This is the first report to show that inflammation and ER stress downregulate the expression of BDH2 in human THP-1 macrophages. PMID:25762501

  13. TLR Stimulation Dynamically Regulates Heme and Iron Export Gene Expression in Macrophages

    PubMed Central

    Philip, Mary; Chiu, Edison Y.; Hajjar, Adeline M.; Abkowitz, Janis L.

    2016-01-01

    Pathogenic bacteria have evolved multiple mechanisms to capture iron or iron-containing heme from host tissues or blood. In response, organisms have developed defense mechanisms to keep iron from pathogens. Very little of the body's iron store is available as free heme; rather nearly all body iron is complexed with heme or other proteins. The feline leukemia virus, subgroup C (FeLV-C) receptor, FLVCR, exports heme from cells. It was unknown whether FLVCR regulates heme-iron availability after infection, but given that other heme regulatory proteins are upregulated in macrophages in response to bacterial infection, we hypothesized that macrophages dynamically regulate FLVCR. We stimulated murine primary macrophages or macrophage cell lines with LPS and found that Flvcr is rapidly downregulated in a TLR4/MD2-dependent manner; TLR1/2 and TLR3 stimulation also decreased Flvcr expression. We identified several candidate TLR-activated transcription factors that can bind to the Flvcr promoter. Macrophages must balance the need to sequester iron from systemic circulating or intracellular pathogens with the macrophage requirement for heme and iron to produce reactive oxygen species. Our findings underscore the complexity of this regulation and point to a new role for FLVCR and heme export in macrophages responses to infection and inflammation. PMID:27006955

  14. Dual Transcriptome Profiling of Leishmania-Infected Human Macrophages Reveals Distinct Reprogramming Signatures

    PubMed Central

    Fernandes, Maria Cecilia; Dillon, Laura A. L.; Belew, Ashton Trey; Bravo, Hector Corrada; Mosser, David M.

    2016-01-01

    ABSTRACT Macrophages are mononuclear phagocytes that constitute a first line of defense against pathogens. While lethal to many microbes, they are the primary host cells of Leishmania spp. parasites, the obligate intracellular pathogens that cause leishmaniasis. We conducted transcriptomic profiling of two Leishmania species and the human macrophage over the course of intracellular infection by using high-throughput RNA sequencing to characterize the global gene expression changes and reprogramming events that underlie the interactions between the pathogen and its host. A systematic exclusion of the generic effects of large-particle phagocytosis revealed a vigorous, parasite-specific response of the human macrophage early in the infection that was greatly tempered at later time points. An analogous temporal expression pattern was observed with the parasite, suggesting that much of the reprogramming that occurs as parasites transform into intracellular forms generally stabilizes shortly after entry. Following that, the parasite establishes an intracellular niche within macrophages, with minimal communication between the parasite and the host cell later during the infection. No significant difference was observed between parasite species transcriptomes or in the transcriptional response of macrophages infected with each species. Our comparative analysis of gene expression changes that occur as mouse and human macrophages are infected by Leishmania spp. points toward a general signature of the Leishmania-macrophage infectome. PMID:27165796

  15. Some strains of Plasmodium falciparum, a human malaria parasite, evade the complement-like system of Anopheles gambiae mosquitoes.

    PubMed

    Molina-Cruz, Alvaro; DeJong, Randall J; Ortega, Corrie; Haile, Ashley; Abban, Ekua; Rodrigues, Janneth; Jaramillo-Gutierrez, Giovanna; Barillas-Mury, Carolina

    2012-07-10

    Plasmodium falciparum lines differ in their ability to infect mosquitoes. The Anopheles gambiae L3-5 refractory (R) line melanizes most Plasmodium species, including the Brazilian P. falciparum 7G8 line, but it is highly susceptible to some African P. falciparum strains such as 3D7, NF54, and GB4. We investigated whether these lines differ in their ability to evade the mosquito immune system. Silencing key components of the mosquito complement-like system [thioester-containing protein 1 (TEP1), leucine-rich repeat protein 1, and Anopheles Plasmodium-responsive leucine-rich repeat protein 1] prevented melanization of 7G8 parasites, reverting the refractory phenotype. In contrast, it had no effect on the intensity of infection with NF54, suggesting that this line is able to evade TEP1-mediated lysis. When R females were coinfected with a line that is melanized (7G8) and a line that survives (3D7), the coinfection resulted in mixed infections with both live and encapsulated parasites on individual midguts. This finding shows that survival of individual parasites is parasite-specific and not systemic in nature, because parasites can evade TEP1-mediated lysis even when other parasites are melanized in the same midgut. When females from an extensive genetic cross between R and susceptible A. gambiae (G3) mosquitoes were infected with P. berghei, encapsulation was strongly correlated with the TEP1-R1 allele. However, P. falciparum 7G8 parasites were no longer encapsulated by females from this cross, indicating that the TEP1-R1 allele is not sufficient to melanize this line. Evasion of the A. gambiae immune system by P. falciparum may be the result of parasite adaptation to sympatric mosquito vectors and may be an important factor driving malaria transmission. PMID:22623529

  16. Plant Defense against Insect Herbivores

    PubMed Central

    Fürstenberg-Hägg, Joel; Zagrobelny, Mika; Bak, Søren

    2013-01-01

    Plants have been interacting with insects for several hundred million years, leading to complex defense approaches against various insect feeding strategies. Some defenses are constitutive while others are induced, although the insecticidal defense compound or protein classes are often similar. Insect herbivory induce several internal signals from the wounded tissues, including calcium ion fluxes, phosphorylation cascades and systemic- and jasmonate signaling. These are perceived in undamaged tissues, which thereafter reinforce their defense by producing different, mostly low molecular weight, defense compounds. These bioactive specialized plant defense compounds may repel or intoxicate insects, while defense proteins often interfere with their digestion. Volatiles are released upon herbivory to repel herbivores, attract predators or for communication between leaves or plants, and to induce defense responses. Plants also apply morphological features like waxes, trichomes and latices to make the feeding more difficult for the insects. Extrafloral nectar, food bodies and nesting or refuge sites are produced to accommodate and feed the predators of the herbivores. Meanwhile, herbivorous insects have adapted to resist plant defenses, and in some cases even sequester the compounds and reuse them in their own defense. Both plant defense and insect adaptation involve metabolic costs, so most plant-insect interactions reach a stand-off, where both host and herbivore survive although their development is suboptimal. PMID:23681010

  17. Macrophages and the Viral Dissemination Super Highway

    PubMed Central

    Klepper, Arielle; Branch, Andrea D

    2016-01-01

    Monocytes and macrophages are key components of the innate immune system yet they are often the victims of attack by infectious agents. This review examines the significance of viral infection of macrophages. The central hypothesis is that macrophage tropism enhances viral dissemination and persistence, but these changes may come at the cost of reduced replication in cells other than macrophages. PMID:26949751

  18. Synthetic plant defense elicitors

    PubMed Central

    Bektas, Yasemin; Eulgem, Thomas

    2015-01-01

    To defend themselves against invading pathogens plants utilize a complex regulatory network that coordinates extensive transcriptional and metabolic reprogramming. Although many of the key players of this immunity-associated network are known, the details of its topology and dynamics are still poorly understood. As an alternative to forward and reverse genetic studies, chemical genetics-related approaches based on bioactive small molecules have gained substantial popularity in the analysis of biological pathways and networks. Use of such molecular probes can allow researchers to access biological space that was previously inaccessible to genetic analyses due to gene redundancy or lethality of mutations. Synthetic elicitors are small drug-like molecules that induce plant defense responses, but are distinct from known natural elicitors of plant immunity. While the discovery of some synthetic elicitors had already been reported in the 1970s, recent breakthroughs in combinatorial chemical synthesis now allow for inexpensive high-throughput screens for bioactive plant defense-inducing compounds. Along with powerful reverse genetics tools and resources available for model plants and crop systems, comprehensive collections of new synthetic elicitors will likely allow plant scientists to study the intricacies of plant defense signaling pathways and networks in an unparalleled fashion. As synthetic elicitors can protect crops from diseases, without the need to be directly toxic for pathogenic organisms, they may also serve as promising alternatives to conventional biocidal pesticides, which often are harmful for the environment, farmers and consumers. Here we are discussing various types of synthetic elicitors that have been used for studies on the plant immune system, their modes-of-action as well as their application in crop protection. PMID:25674095

  19. Nanomaterials for Defense Applications

    NASA Astrophysics Data System (ADS)

    Turaga, Uday; Singh, Vinitkumar; Lalagiri, Muralidhar; Kiekens, Paul; Ramkumar, Seshadri S.

    Nanotechnology has found a number of applications in electronics and healthcare. Within the textile field, applications of nanotechnology have been limited to filters, protective liners for chemical and biological clothing and nanocoatings. This chapter presents an overview of the applications of nanomaterials such as nanofibers and nanoparticles that are of use to military and industrial sectors. An effort has been made to categorize nanofibers based on the method of production. This chapter particularly focuses on a few latest developments that have taken place with regard to the application of nanomaterials such as metal oxides in the defense arena.

  20. The Role of Prostate Apoptosis Response-4 (Par-4) in Mycobacterium tuberculosis Infected Macrophages.

    PubMed

    Han, Ji-Ye; Lim, Yun-Ji; Choi, Ji-Ae; Lee, Jung-Hwan; Jo, Sung-Hee; Oh, Sung-Man; Song, Chang-Hwa

    2016-01-01

    Prostate apoptosis response-4 (Par-4) is a tumor suppressor protein that forms a complex with glucose-regulated protein 78 (GRP78) to induce apoptosis. Previously, we reported that ER stress-induced apoptosis is a critical host defense mechanism against Mycobacterium tuberculosis (Mtb). We sought to understand the role of Par-4 during ER stress-induced apoptosis in response to mycobacterial infection. Par-4 and GRP78 protein levels increased in response Mtb (strain: H37Ra) infection. Furthermore, Par-4 and GRP78 translocate to the surface of Mtb H37Ra-infected macrophages and induce apoptosis via caspase activation. NF-κB activation, Mtb-mediated ER stress, and Par-4 production were significantly diminished in macrophages with inhibited ROS production. To test Par-4 function during mycobacterial infection, we analyzed intracellular survival of Mtb H37Ra in macrophages with Par-4 overexpression or knockdown. Mtb H37Ra growth was significantly reduced in Par-4 overexpressing macrophages and increased in knockdown macrophages. We also observed increased Par-4, GRP78, and caspases activation in Bacillus Calmette-Guérin (BCG)-infected prostate cancer cells. Our data demonstrate that Par-4 is associated with ER stress-induced apoptosis resulting in reduced intracellular survival of mycobacteria. BCG treatment increases Par-4-dependent caspase activation in prostate cancer cells. These results suggest ER stress-induced Par-4 acts as an important defense mechanism against mycobacterial infection and regulates cancer. PMID:27552917

  1. The Role of Prostate Apoptosis Response-4 (Par-4) in Mycobacterium tuberculosis Infected Macrophages

    PubMed Central

    Han, Ji-Ye; Lim, Yun-Ji; Choi, Ji-Ae; Lee, Jung-hwan; Jo, Sung-Hee; Oh, Sung-Man; Song, Chang-Hwa

    2016-01-01

    Prostate apoptosis response-4 (Par-4) is a tumor suppressor protein that forms a complex with glucose-regulated protein 78 (GRP78) to induce apoptosis. Previously, we reported that ER stress-induced apoptosis is a critical host defense mechanism against Mycobacterium tuberculosis (Mtb). We sought to understand the role of Par-4 during ER stress-induced apoptosis in response to mycobacterial infection. Par-4 and GRP78 protein levels increased in response Mtb (strain: H37Ra) infection. Furthermore, Par-4 and GRP78 translocate to the surface of Mtb H37Ra-infected macrophages and induce apoptosis via caspase activation. NF-κB activation, Mtb-mediated ER stress, and Par-4 production were significantly diminished in macrophages with inhibited ROS production. To test Par-4 function during mycobacterial infection, we analyzed intracellular survival of Mtb H37Ra in macrophages with Par-4 overexpression or knockdown. Mtb H37Ra growth was significantly reduced in Par-4 overexpressing macrophages and increased in knockdown macrophages. We also observed increased Par-4, GRP78, and caspases activation in Bacillus Calmette-Guérin (BCG)-infected prostate cancer cells. Our data demonstrate that Par-4 is associated with ER stress-induced apoptosis resulting in reduced intracellular survival of mycobacteria. BCG treatment increases Par-4-dependent caspase activation in prostate cancer cells. These results suggest ER stress-induced Par-4 acts as an important defense mechanism against mycobacterial infection and regulates cancer. PMID:27552917

  2. Escherichia coli and Candida albicans Induced Macrophage Extracellular Trap-Like Structures with Limited Microbicidal Activity

    PubMed Central

    Liao, Chengshui; Liu, Xiaolei; Du, Jing; Shi, Haining; Wang, Xuelin; Bai, Xue; Peng, Peng; Yu, Lu; Wang, Feng; Zhao, Ying; Liu, Mingyuan

    2014-01-01

    The formation of extracellular traps (ETs) has recently been recognized as a novel defense mechanism in several types of innate immune cells. It has been suggested that these structures are toxic to microbes and contribute significantly to killing several pathogens. However, the role of ETs formed by macrophages (METs) in defense against microbes remains little known. In this study, we demonstrated that a subset of murine J774A.1 macrophage cell line (8% to 17%) and peritoneal macrophages (8.5% to 15%) form METs-like structures (METs-LS) in response to Escherichia coli and Candida albicans challenge. We found only a portion of murine METs-LS, which are released by dying macrophages, showed detectable killing effects on trapped E. coli but not C. albicans. Fluorescence and scanning electron microscopy analyses revealed that, in vitro, both microorganisms were entrapped in J774A.1 METs-LS composed of DNA and microbicidal proteins such as histone, myeloperoxidase and lysozyme. DNA components of both nucleus and mitochondrion origins were detectable in these structures. Additionally, METs-LS formation occurred independently of ROS produced by NADPH oxidase, and this process did not result in cell lysis. In summary, our results emphasized that microbes induced METs-LS in murine macrophage cells and that the microbicidal activity of these METs-LS differs greatly. We propose the function of METs-LS is to contain invading microbes at the infection site, thereby preventing the systemic diffusion of them, rather than significantly killing them. PMID:24587206

  3. Bringing macromolecules into cells and evading endosomes by oxidized carbon nanoparticles.

    PubMed

    Arayachukiat, Sunatda; Seemork, Jiraporn; Pan-In, Porntip; Amornwachirabodee, Kittima; Sangphech, Naunpun; Sansureerungsikul, Titiporn; Sathornsantikun, Kamonluck; Vilaivan, Chotima; Shigyou, Kazuki; Pienpinijtham, Prompong; Vilaivan, Tirayut; Palaga, Tanapat; Banlunara, Wijit; Hamada, Tsutomu; Wanichwecharungruang, Supason

    2015-05-13

    A great challenge exists in finding safe, simple, and effective delivery strategies to bring matters across cell membrane. Popular methods such as viral vectors, positively charged particles and cell penetrating peptides possess some of the following drawbacks: safety issues, lysosome trapping, limited loading capacity, and toxicity, whereas electroporation produces severe damages on both cargoes and cells. Here, we show that a serendipitously discovered, relatively nontoxic, water dispersible, stable, negatively charged, oxidized carbon nanoparticle, prepared from graphite, could deliver macromolecules into cells, without getting trapped in a lysosome. The ability of the particles to induce transient pores on lipid bilayer membranes of cell-sized liposomes was demonstrated. Delivering 12-base-long pyrrolidinyl peptide nucleic acids with d-prolyl-(1S,2S)-2-aminocyclopentanecarboxylic acid backbone (acpcPNA) complementary to the antisense strand of the NF-κB binding site in the promoter region of the Il6 gene into the macrophage cell line, RAW 264.7, by our particles resulted in an obvious accumulation of the acpcPNAs in the nucleus and decreased Il6 mRNA and IL-6 protein levels upon stimulation. We anticipate this work to be a starting point in a new drug delivery strategy, which involves the nanoparticle that can induce a transient pore on the lipid bilayer membrane. PMID:25849219

  4. PPARs in alveolar macrophage biology.

    PubMed

    Smith, Monica R; Standiford, Theodore J; Reddy, Raju C

    2007-01-01

    PPARs, most notably PPAR-gamma, play a crucial role in regulating the activation of alveolar macrophages, which in turn occupy a pivotal place in the immune response to pathogens and particulates drawn in with inspired air. In this review, we describe the dual role of the alveolar macrophage as both a first-line defender through its phagocytotic activity and a regulator of the immune response. Depending on its state of activation, the alveolar macrophage may either enhance or suppress different aspects of immune function in the lung. We then review the role of PPAR-gamma and its ligands in deactivating alveolar macrophages-thus limiting the inflammatory response that, if unchecked, could threaten the essential respiratory function of the alveolus-while upregulating the cell's phagocytotic activity. Finally, we examine the role that inadequate or inappropriate PPAR-gamma responses play in specific lung diseases. PMID:18000531

  5. Micronuclei in human alveolar macrophages.

    PubMed

    D'Agostini, F; Bonatti, S; Oddera, S; De Flora, S

    1992-01-01

    Occurrence of micronuclei was monitored in pulmonary alveolar macrophages collected from 31 individuals undergoing diagnostic bronchoalveolar lavage. The overall frequency of micronucleated cells was 3.88 +/- 1.84/1000, without any significant difference attributable to sex, age, pathology, occupation, or smoking habits. The lack of influence of cigarette smoke on this clastogenicity index presumably reflects the very low rate of mitoses of macrophages in the alveolar lumen. PMID:1579732

  6. Proteomic Analysis of Salmonella enterica Serovar Typhimurium Isolated from RAW 264.7 Macrophages: identification of a novel protein that contributes to the replication of serovar Typhimurium inside macrophages

    SciTech Connect

    Shi, Liang; Adkins, Joshua N.; Coleman, James R.; Schepmoes, Athena A.; Dohnalkova, Alice; Mottaz, Heather M.; Norbeck, Angela D.; Purvine, Samuel O.; Manes, Nathan P.; Smallwood, Heather S.; Wang, Haixing H.; Forbes, John; Gros, Philippe; Uzzau, Sergio; Rodland, Karin D.; Heffron, Fred; Smith, Richard D.; Squier, Thomas C.

    2006-09-01

    ABSTRACT: To evade host resistance mechanisms, Salmonella enterica serovar Typhimurium (STM), a facultative intracellular pathogen, must alter its proteome following macrophage infection. To identify new colonization and virulence factors that mediate STM pathogenesis, we have isolated STM cells from RAW 264.7 macrophages at various time-points following infection and used a liquid chromatography-mass spectrometry (LC-MS)-based proteomic approach to detect the changes in STM protein abundances. Because host resistance to STM infection is strongly modulated by the expression of a functional host resistant regulator, i.e., natural resistance associated macrophage protein 1 (Nramp1, also called Slc11a1), we have also examined the effects of Nramp1 activity on the changes of STM protein abundances. A total of 315 STM proteins have been identified from isolated STM cells, which are largely house-keeping proteins whose abundances remain relatively constant during the time-course of infection. However, 39 STM proteins are strongly induced after infection, suggesting their involvement in modulating colonization and infection. Of the 39 induced proteins, 6 proteins are specifically modulated by Nramp1 activity, including STM3117, as well as STM3118-3119 whose time-dependent abundance changes were confirmed using Western blot analysis. Deletion of the gene encoding STM3117 resulted in a dramatic reduction in the ability of STM to colonize wild-type RAW 264.7 macrophages, demonstrating a critical involvement of STM3117 in promoting the replication of STM inside macrophages. The predicted function common for STM3117-3119 is biosynthesis and modification of the peptidoglycan layer of STM cell wall, emphasizing their important roles in the colonization of macrophages by Salmonella.

  7. Macrophage Migration Inhibitory Factor (MIF): A Key Player in Protozoan Infections

    PubMed Central

    de Dios Rosado, Juan; Rodriguez-Sosa, Miriam

    2011-01-01

    Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine produced by the pituitary gland and multiple cell types, including macrophages (Mø), dendritic cells (DC) and T-cells. Upon releases MIF modulates the expression of several inflammatory molecules, such as TNF-α, nitric oxide and cyclooxygenase 2 (COX-2). These important MIF characteristics have prompted investigators to study its role in parasite infections. Several reports have demonstrated that MIF plays either a protective or deleterious role in the immune response to different pathogens. Here, we review the role of MIF in the host defense response to some important protozoan infections. PMID:22110378

  8. Light regulation of plant defense.

    PubMed

    Ballaré, Carlos L

    2014-01-01

    Precise allocation of limited resources between growth and defense is critical for plant survival. In shade-intolerant species, perception of competition signals by informational photoreceptors activates shade-avoidance responses and reduces the expression of defenses against pathogens and insects. The main mechanism underlying defense suppression is the simultaneous downregulation of jasmonate and salicylic acid signaling by low ratios of red:far-red radiation. Inactivation of phytochrome B by low red:far-red ratios appears to suppress jasmonate responses by altering the balance between DELLA and JASMONATE ZIM DOMAIN (JAZ) proteins in favor of the latter. Solar UVB radiation is a positive modulator of plant defense, signaling through jasmonate-dependent and jasmonate-independent pathways. Light, perceived by phytochrome B and presumably other photoreceptors, helps plants concentrate their defensive arsenals in photosynthetically valuable leaves. The discovery of connections between photoreceptors and defense signaling is revealing novel mechanisms that control key resource allocation decisions in plant canopies. PMID:24471835

  9. Boron Induces Lymphocyte Proliferation and Modulates the Priming Effects of Lipopolysaccharide on Macrophages.

    PubMed

    Routray, Indusmita; Ali, Shakir

    2016-01-01

    Chemical mediators of inflammation (CMI) are important in host defense against infection. The reduced capacity of host to induce the secretion of these mediators following infection is one of the factors in host susceptibility to infection. Boron, which has been suggested for its role in infection, is reported in this study to increase lymphocyte proliferation and the secretion of CMI by the lipopolysaccharide (LPS)-stimulated peritoneal macrophages in BALB/c mice. Boron was administered to mice orally as borax at different doses for 10 consecutive days, followed by the stimulation of animals with ovalbumin and isolation of splenocytes for proliferation assay. The lymphocyte subsets were determined by flow cytometry in spleen cell suspension. The mediators of inflammation, TNF-α, IL-6, IL-1β and nitric oxide (NO), were measured in culture supernatant of LPS-primed macrophages isolated from borax treated mice. TNF and ILs were measured by ELISA. NO was determined by Griess test. The expression of inducible nitric oxide synthase (iNOS) in macrophages was studied by confocal microscopy. Results showed a significant increase in T and B cell populations, as indicated by an increase in CD4 and CD19, but not CD8, cells. Boron further stimulated the secretion of TNF-α, IL-6, IL-1β, NO and the expression of iNOS by the LPS-primed macrophages. The effect was dose dependent and most significant at a dose level of 4.6 mg/kg b. wt. Taken together, the study concludes that boron at physiological concentration induces lymphocyte proliferation and increases the synthesis and secretion of pro-inflammatory mediators by the LPS-primed macrophages, more specifically the M1 macrophages, possibly acting through Toll-like receptor. The study implicates boron as a regulator of the immune and inflammatory reactions and macrophage polarization, thus playing an important role in augmenting host defense against infection, with possible role in cancer and other diseases. PMID:26934748

  10. Boron Induces Lymphocyte Proliferation and Modulates the Priming Effects of Lipopolysaccharide on Macrophages

    PubMed Central

    Routray, Indusmita; Ali, Shakir

    2016-01-01

    Chemical mediators of inflammation (CMI) are important in host defense against infection. The reduced capacity of host to induce the secretion of these mediators following infection is one of the factors in host susceptibility to infection. Boron, which has been suggested for its role in infection, is reported in this study to increase lymphocyte proliferation and the secretion of CMI by the lipopolysaccharide (LPS)-stimulated peritoneal macrophages in BALB/c mice. Boron was administered to mice orally as borax at different doses for 10 consecutive days, followed by the stimulation of animals with ovalbumin and isolation of splenocytes for proliferation assay. The lymphocyte subsets were determined by flow cytometry in spleen cell suspension. The mediators of inflammation, TNF-α, IL-6, IL-1β and nitric oxide (NO), were measured in culture supernatant of LPS-primed macrophages isolated from borax treated mice. TNF and ILs were measured by ELISA. NO was determined by Griess test. The expression of inducible nitric oxide synthase (iNOS) in macrophages was studied by confocal microscopy. Results showed a significant increase in T and B cell populations, as indicated by an increase in CD4 and CD19, but not CD8, cells. Boron further stimulated the secretion of TNF-α, IL-6, IL-1β, NO and the expression of iNOS by the LPS-primed macrophages. The effect was dose dependent and most significant at a dose level of 4.6 mg/kg b. wt. Taken together, the study concludes that boron at physiological concentration induces lymphocyte proliferation and increases the synthesis and secretion of pro-inflammatory mediators by the LPS-primed macrophages, more specifically the M1 macrophages, possibly acting through Toll-like receptor. The study implicates boron as a regulator of the immune and inflammatory reactions and macrophage polarization, thus playing an important role in augmenting host defense against infection, with possible role in cancer and other diseases. PMID:26934748

  11. Intracellular Shigella remodels its LPS to dampen the innate immune recognition and evade inflammasome activation

    PubMed Central

    Paciello, Ida; Silipo, Alba; Lembo-Fazio, Luigi; Curcurù, Laura; Zumsteg, Anna; Noël, Gaëlle; Ciancarella, Valeria; Sturiale, Luisa; Molinaro, Antonio; Bernardini, Maria Lina

    2013-01-01

    LPS is a potent bacterial effector triggering the activation of the innate immune system following binding with the complex CD14, myeloid differentiation protein 2, and Toll-like receptor 4. The LPS of the enteropathogen Shigella flexneri is a hexa-acylated isoform possessing an optimal inflammatory activity. Symptoms of shigellosis are produced by severe inflammation caused by the invasion process of Shigella in colonic and rectal mucosa. Here we addressed the question of the role played by the Shigella LPS in eliciting a dysregulated inflammatory response of the host. We unveil that (i) Shigella is able to modify the LPS composition, e.g., the lipid A and core domains, during proliferation within epithelial cells; (ii) the LPS of intracellular bacteria (iLPS) and that of bacteria grown in laboratory medium differ in the number of acyl chains in lipid A, with iLPS being the hypoacylated; (iii) the immunopotential of iLPS is dramatically lower than that of bacteria grown in laboratory medium; (iv) both LPS forms mainly signal through the Toll-like receptor 4/myeloid differentiation primary response gene 88 pathway; (v) iLPS down-regulates the inflammasome-mediated release of IL-1β in Shigella-infected macrophages; and (vi) iLPS exhibits a reduced capacity to prime polymorfonuclear cells for an oxidative burst. We propose a working model whereby the two forms of LPS might govern different steps of the invasive process of Shigella. In the first phases, the bacteria, decorated with hypoacylated LPS, are able to lower the immune system surveillance, whereas, in the late phases, shigellae harboring immunopotent LPS are fully recognized by the immune system, which can then successfully resolve the infection. PMID:24167293

  12. Generation and Identification of GM-CSF Derived Alveolar-like Macrophages and Dendritic Cells From Mouse Bone Marrow.

    PubMed

    Dong, Yifei; Arif, Arif A; Poon, Grace F T; Hardman, Blair; Dosanjh, Manisha; Johnson, Pauline

    2016-01-01

    Macrophages and dendritic cells (DCs) are innate immune cells found in tissues and lymphoid organs that play a key role in the defense against pathogens. However, they are difficult to isolate in sufficient numbers to study them in detail, therefore, in vitro models have been developed. In vitro cultures of bone marrow-derived macrophages and dendritic cells are well-established and valuable methods for immunological studies. Here, a method for culturing and identifying both DCs and macrophages from a single culture of primary mouse bone marrow cells using the cytokine granulocyte macrophage colony-stimulating factor (GM-CSF) is described. This protocol is based on the established procedure first developed by Lutz et al. in 1999 for bone marrow-derived DCs. The culture is heterogeneous, and MHCII and fluoresceinated hyaluronan (FL-HA) are used to distinguish macrophages from immature and mature DCs. These GM-CSF derived macrophages provide a convenient source of in vitro derived macrophages that closely resemble alveolar macrophages in both phenotype and function. PMID:27404290

  13. Assessment of carbon nanoparticle exposure on murine macrophage function

    NASA Astrophysics Data System (ADS)

    Suro-Maldonado, Raquel M.

    There is growing concern about the potential cytotoxicity of nanoparticles. Exposure to respirable ultrafine particles (2.5uM) can adversely affect human health and have been implicated with episodes of increased respiratory diseases such as asthma and allergies. Nanoparticles are of particular interest because of their ability to penetrate into the lung and potentially elicit health effects triggering immune responses. Nanoparticles are structures and devises with length scales in the 1 to 100-nanometer range. Black carbon (BC) nanoparticles have been observed to be products of combustion, especially flame combustion and multi-walled carbon nanotubes (MWCNT) have been shown to be found in both indoor and outdoor air. Furthermore, asbestos, which have been known to cause mesothelioma as well as lung cancer, have been shown to be structurally identical to MWCNTs. The aims of these studies were to examine the effects of carbon nanoparticles on murine macrophage function and clearance mechanisms. Macrophages are immune cells that function as the first line of defense against invading pathogens and are likely to be amongst the first cells affected by nanoparticles. Our research focused on two manufactured nanoparticles, MWCNT and BC. The two were tested against murine-derived macrophages in a chronic contact model. We hypothesized that long-term chronic exposure to carbon nanoparticles would decrease macrophages ability to effectively respond to immunological challenge. Production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), cell surface macrophage; activation markers, reactive oxygen species formation (ROS), and antigen processing and presentation were examined in response to lipopolysaccharide (LPS) following a 144hr exposure to the particulates. Data demonstrated an increase in TNF-alpha, and NO production; a decrease in phagocytosis and antigen processing and presentation; and a decrease in the expression levels of cell surface macrophage

  14. Hybrid nanoparticles improve targeting to inflammatory macrophages through phagocytic signals.

    PubMed

    Bagalkot, Vaishali; Badgeley, Marcus A; Kampfrath, Thomas; Deiuliis, Jeffrey A; Rajagopalan, Sanjay; Maiseyeu, Andrei

    2015-11-10

    Macrophages are innate immune cells with great phenotypic plasticity, which allows them to regulate an array of physiological processes such as host defense, tissue repair, and lipid/lipoprotein metabolism. In this proof-of-principle study, we report that macrophages of the M1 inflammatory phenotype can be selectively targeted by model hybrid lipid-latex (LiLa) nanoparticles bearing phagocytic signals. We demonstrate a simple and robust route to fabricate nanoparticles and then show their efficacy through imaging and drug delivery in inflammatory disease models of atherosclerosis and obesity. Self-assembled LiLa nanoparticles can be modified with a variety of hydrophobic entities such as drug cargos, signaling lipids, and imaging reporters resulting in sub-100nm nanoparticles with low polydispersities. The optimized theranostic LiLa formulation with gadolinium, fluorescein and "eat-me" phagocytic signals (Gd-FITC-LiLa) a) demonstrates high relaxivity that improves magnetic resonance imaging (MRI) sensitivity, b) encapsulates hydrophobic drugs at up to 60% by weight, and c) selectively targets inflammatory M1 macrophages concomitant with controlled release of the payload of anti-inflammatory drug. The mechanism and kinetics of the payload discharge appeared to be phospholipase A2 activity-dependent, as determined by means of intracellular Förster resonance energy transfer (FRET). In vivo, LiLa targets M1 macrophages in a mouse model of atherosclerosis, allowing noninvasive imaging of atherosclerotic plaque by MRI. In the context of obesity, LiLa particles were selectively deposited to M1 macrophages within inflamed adipose tissue, as demonstrated by single-photon intravital imaging in mice. Collectively, our results suggest that phagocytic signals can preferentially target inflammatory macrophages in experimental models of atherosclerosis and obesity, thus opening the possibility of future clinical applications that diagnose/treat these conditions. Tunable Li

  15. Hybrid nanoparticles improve targeting to inflammatory macrophages through phagocytic signals

    PubMed Central

    Bagalkot, Vaishali; Badgeley, Marcus A.; Kampfrath, Thomas; Deiuliis, Jeffrey A.; Rajagopalan, Sanjay; Maiseyeu, Andrei

    2016-01-01

    Macrophages are innate immune cells with great phenotypic plasticity, which allows them to regulate an array of physiological processes such as host defense, tissue repair, and lipid/lipoprotein metabolism. In this proof-of-principle study, we report that macrophages of the M1 inflammatory phenotype can be selectively targeted by model hybrid lipid–latex (LiLa) nanoparticles bearing phagocytic signals. We demonstrate a simple and robust route to fabricate nanoparticles and then show their efficacy through imaging and drug delivery in inflammatory disease models of atherosclerosis and obesity. Self-assembled LiLa nanoparticles can be modified with a variety of hydrophobic entities such as drug cargos, signaling lipids, and imaging reporters resulting in sub-100 nm nano-particles with low polydispersities. The optimized theranostic LiLa formulation with gadolinium, fluorescein and “eat-me” phagocytic signals (Gd-FITC-LiLa) a) demonstrates high relaxivity that improves magnetic resonance imaging (MRI) sensitivity, b) encapsulates hydrophobic drugs at up to 60% by weight, and c) selectively targets inflammatory M1 macrophages concomitant with controlled release of the payload of anti-inflammatory drug. The mechanism and kinetics of the payload discharge appeared to be phospholipase A2 activity-dependent, as determined by means of intracellular Förster resonance energy transfer (FRET). In vivo, LiLa targets M1 macrophages in a mouse model of atherosclerosis, allowing noninvasive imaging of atherosclerotic plaque by MRI. In the context of obesity, LiLa particles were selectively deposited to M1 macrophages within inflamed adipose tissue, as demonstrated by single-photon intravital imaging in mice. Collectively, our results suggest that phagocytic signals can preferentially target inflammatory macrophages in experimental models of atherosclerosis and obesity, thus opening the possibility of future clinical applications that diagnose/treat these conditions. Tunable

  16. Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA.

    PubMed

    Pel, Michiel J C; van Dijken, Anja J H; Bardoel, Bart W; Seidl, Michael F; van der Ent, Sjoerd; van Strijp, Jos A G; Pieterse, Corné M J

    2014-07-01

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of bacterial species. In addition, we investigated the role of AprA in virulence of the bacterial plant pathogen P. syringae pv. tomato DC3000. The AprA-deficient DC3000 ΔaprA knockout mutant was significantly less virulent on both tomato and Arabidopsis thaliana. Moreover, infiltration of A. thaliana Col-0 leaves with DC3000 ΔaprA evoked a significantly higher level of expression of the defense-related genes FRK1 and PR-1 than did wild-type DC3000. In the flagellin receptor mutant fls2, pathogen virulence and defense-related gene activation did not differ between DC3000 and DC3000 ΔaprA. Together, these results suggest that AprA of DC3000 is important for evasion of recognition by the FLS2 receptor, allowing wild-type DC3000 to be more virulent on its host plant than AprA-deficient DC3000 ΔaprA. To provide further evidence for the role of DC3000 AprA in host immune evasion, we overexpressed the AprA inhibitory peptide AprI of DC3000 in A. thaliana to counteract the immune evasive capacity of DC3000 AprA. Ectopic expression of aprI in A. thaliana resulted in an enhanced level of resistance against wild-type DC3000, while the already elevated level of resistance against DC3000 ΔaprA remained unchanged. Together, these results indicate that evasion of host immunity by the alkaline protease AprA is important for full virulence of strain DC3000 and likely acts by preventing flagellin monomers from being recognized by its cognate immune receptor. PMID:24654978

  17. Developmental derivation of embryonic and adult macrophages.

    PubMed

    Shepard, J L; Zon, L I

    2000-01-01

    The macrophage cell lineage continually arises from hematopoietic stem cells during embryonic, fetal, and adult life. Previous theories proposed that macrophages are the recent progeny of bone marrow-derived monocytes and that they function primarily in phagocytosis. More recently, however, observations have shown that the ontogeny of macrophages in early mouse and human embryos is different from that occurring during adult development, and that the embryonic macrophages do not follow the monocyte pathway. Fetal macrophages are thought to differentiate from yolk sac-derived primitive macrophages before the development of adult monocytes. Further support for a separate lineage of fetal macrophages has come from studies of several species, including chicken, zebrafish, Xenopus, Drosophila, and C. elegans. The presence of fetal macrophages in PU.1-null mice indicates their independence from monocyte precursors and their existence as an alternative macrophage lineage. PMID:10608497

  18. 1,25-Dihydroxyvitamin D Modulates Antibacterial and Inflammatory Response in Human Cigarette Smoke-Exposed Macrophages

    PubMed Central

    Heulens, Nele; Korf, Hannelie; Mathyssen, Carolien; Everaerts, Stephanie; De Smidt, Elien; Dooms, Christophe; Yserbyt, Jonas; Gysemans, Conny; Gayan-Ramirez, Ghislaine; Mathieu, Chantal; Janssens, Wim

    2016-01-01

    Cigarette smoking is associated with increased inflammation and defective antibacterial responses in the airways. Interestingly, vitamin D has been shown to suppress inflammation and to improve antibacterial defense. However, it is currently unknown whether vitamin D may modulate inflammation and antibacterial defects in human cigarette smoke (CS)-exposed airways. To explore these unresolved issues, alveolar macrophages obtained from non-smoking and smoking subjects as well as human cigarette smoke extract (CSE)-treated THP-1 macrophages were stimulated with 1,25-dihydroxyvitamin D (1,25(OH)2D) to address inflammatory and antibacterial responses. Although basal levels of inflammatory cytokines and chemokines did not differ between non-smoking and smoking subjects, 1,25(OH)2D did reduce levels of IL-6, TNF-α and MCP-1 in alveolar macrophages in response to LPS/IFN-γ, although not statistically significant for TNF-α and IL-6 in smokers. CSE did not significantly alter vitamin D metabolism (expression levels of CYP24A1 or CYP27B1) in THP-1 macrophages. Furthermore, stimulation with 1,25(OH)2D reduced mRNA expression levels and/or protein levels of IL-8, TNF-α and MCP-1 in CSE-treated THP-1 macrophages. 1,25(OH)2D did not improve defects in phagocytosis of E. coli bacteria or the oxidative burst response in CSE-treated THP-1 macrophages or alveolar macrophages from smokers. However, 1,25(OH)2D significantly enhanced mRNA expression and/or protein levels of the antimicrobial peptide cathelicidin in alveolar macrophages and THP-1 macrophages, independently of CS exposure. In conclusion, our results provide the first evidence that vitamin D could be a new strategy for attenuating airway inflammation and improving antibacterial defense in CS-exposed airways. PMID:27513734

  19. Reactive oxygen species in the tumor niche triggers altered activation of macrophages and immunosuppression: Role of fluoxetine.

    PubMed

    Ghosh, Sayan; Mukherjee, Sudeshna; Choudhury, Sreetama; Gupta, Payal; Adhikary, Arghya; Baral, Rathindranath; Chattopadhyay, Sreya

    2015-07-01

    Macrophages are projected as one of the key players responsible for the progression of cancer. Classically activated (M1) macrophages are pro-inflammatory and have a central role in host defense, while alternatively activated (M2) macrophages are associated with immunosuppression. Macrophages residing at the site of neoplastic growth are alternately activated and are referred to as tumor-associated macrophages (TAMs). These "cooperate" with tumor tissue, promoting increased proliferation and immune escape. Selective serotonin reuptake inhibitors like fluoxetine have recently been reported to possess anti-inflammatory activity. We used fluoxetine to target tumor-associated inflammation and consequent alternate polarization of macrophages. We established that murine peritoneal macrophages progressed towards an altered activation state when exposed to cell-free tumor fluid, as evidenced by increased IL-6, IL-4 and IL-10 levels. These polarized macrophages showed significant pro-oxidant bias and increased p65 nuclear localization. It was further observed that these altered macrophages could induce oxidative insult and apoptosis in cultured mouse CD3(+) T cells. To validate these findings, we replicated key experiments in vivo, and observed that there was increased serum IL-6, IL-4 and IL-10 in tumor-bearing animals, with increased % CD206(+) cells within the tumor niche. TAMs showed increased nuclear localization of p65 with decreased Nrf2 expression in the nucleus. These results were associated with increase in apoptosis of CD3(+) T cells co-cultured with TAM-spent media. We could establish that fluoxetine treatment could specifically re-educate the macrophages both in vitro and in vivo by skewing their phenotype such that immune suppression mediated by tumor-dictated macrophages was successfully mitigated. PMID:25819340

  20. Chlamydia muridarum infection of macrophages elicits bactericidal nitric oxide production via reactive oxygen species and cathepsin B.

    PubMed

    Rajaram, Krithika; Nelson, David E

    2015-08-01

    The ability of certain species of Chlamydia to inhibit the biogenesis of phagolysosomes permits their survival and replication within macrophages. The survival of macrophage-adapted chlamydiae correlates with the multiplicity of infection (MOI), and optimal chlamydial growth occurs in macrophages infected at an MOI of ≤1. In this study, we examined the replicative capacity of Chlamydia muridarum in the RAW 264.7 murine macrophage cell line at different MOIs. C. muridarum productively infected these macrophages at low MOIs but yielded few viable elementary bodies (EBs) when macrophages were infected at a moderate (10) or high (100) MOI. While high MOIs caused cytotoxicity and irreversible host cell death, macrophages infected at a moderate MOI did not show signs of cytotoxicity until late in the infectious cycle. Inhibition of host protein synthesis rescued C. muridarum in macrophages infected at a moderate MOI, implying that chlamydial growth was blocked by activated defense mechanisms. Conditioned medium from these macrophages was antichlamydial and contained elevated levels of interleukin 1β (IL-1β), IL-6, IL-10, and beta interferon (IFN-β). Macrophage activation depended on Toll-like receptor 2 (TLR2) signaling, and cytokine production required live, transcriptionally active chlamydiae. A hydroxyl radical scavenger and inhibitors of inducible nitric oxide synthase (iNOS) and cathepsin B also reversed chlamydial killing. High levels of reactive oxygen species (ROS) led to an increase in cathepsin B activity, and pharmacological inhibition of ROS and cathepsin B reduced iNOS expression. Our data demonstrate that MOI-dependent TLR2 activation of macrophages results in iNOS induction via a novel ROS- and cathepsin-dependent mechanism to facilitate C. muridarum clearance. PMID:26015483

  1. Polyamine transporter in Streptococcus pneumoniae is essential for evading early innate immune responses in pneumococcal pneumonia

    PubMed Central

    Rai, Aswathy N.; Thornton, Justin A.; Stokes, John; Sunesara, Imran; Swiatlo, Edwin; Nanduri, Bindu

    2016-01-01

    Streptococcus pneumoniae is the most common bacterial etiology of pneumococcal pneumonia in adults worldwide. Genomic plasticity, antibiotic resistance and extreme capsular antigenic variation complicates the design of effective therapeutic strategies. Polyamines are ubiquitous small cationic molecules necessary for full expression of pneumococcal virulence. Polyamine transport system is an attractive therapeutic target as it is highly conserved across pneumococcal serotypes. In this study, we compared an isogenic deletion strain of S. pneumoniae TIGR4 in polyamine transport operon (ΔpotABCD) with the wild type in a mouse model of pneumococcal pneumonia. Our results show that the wild type persists in mouse lung 24 h post infection while the mutant strain is cleared by host defense mechanisms. We show that intact potABCD is required for survival in the host by providing resistance to neutrophil killing. Comparative proteomics analysis of murine lungs infected with wild type and ΔpotABCD pneumococci identified expression of proteins that could confer protection to wild type strain and help establish infection. We identified ERM complex, PGLYRP1, PTPRC/CD45 and POSTN as new players in the pathogenesis of pneumococcal pneumonia. Additionally, we found that deficiency of polyamine transport leads to up regulation of the polyamine synthesis genes speE and cad in vitro. PMID:27247105

  2. Polyamine transporter in Streptococcus pneumoniae is essential for evading early innate immune responses in pneumococcal pneumonia.

    PubMed

    Rai, Aswathy N; Thornton, Justin A; Stokes, John; Sunesara, Imran; Swiatlo, Edwin; Nanduri, Bindu

    2016-01-01

    Streptococcus pneumoniae is the most common bacterial etiology of pneumococcal pneumonia in adults worldwide. Genomic plasticity, antibiotic resistance and extreme capsular antigenic variation complicates the design of effective therapeutic strategies. Polyamines are ubiquitous small cationic molecules necessary for full expression of pneumococcal virulence. Polyamine transport system is an attractive therapeutic target as it is highly conserved across pneumococcal serotypes. In this study, we compared an isogenic deletion strain of S. pneumoniae TIGR4 in polyamine transport operon (ΔpotABCD) with the wild type in a mouse model of pneumococcal pneumonia. Our results show that the wild type persists in mouse lung 24 h post infection while the mutant strain is cleared by host defense mechanisms. We show that intact potABCD is required for survival in the host by providing resistance to neutrophil killing. Comparative proteomics analysis of murine lungs infected with wild type and ΔpotABCD pneumococci identified expression of proteins that could confer protection to wild type strain and help establish infection. We identified ERM complex, PGLYRP1, PTPRC/CD45 and POSTN as new players in the pathogenesis of pneumococcal pneumonia. Additionally, we found that deficiency of polyamine transport leads to up regulation of the polyamine synthesis genes speE and cad in vitro. PMID:27247105

  3. Inhibition of Nuclear Factor-Kappa B Activation Decreases Survival of Mycobacterium tuberculosis in Human Macrophages

    PubMed Central

    Chmura, Kathryn; Ovrutsky, Alida R.; Su, Wen-Lin; Griffin, Laura; Pyeon, Dohun; McGibney, Mischa T.; Strand, Matthew J.; Numata, Mari; Murakami, Seiji; Gaido, Loretta; Honda, Jennifer R.; Kinney, William H.; Oberley-Deegan, Rebecca E.; Voelker, Dennis R.; Ordway, Diane J.; Chan, Edward D.

    2013-01-01

    Nuclear factor-kappa B (NFκB) is a ubiquitous transcription factor that mediates pro-inflammatory responses required for host control of many microbial pathogens; on the other hand, NFκB has been implicated in the pathogenesis of other inflammatory and infectious diseases. Mice with genetic disruption of the p50 subunit of NFκB are more likely to succumb to Mycobacterium tuberculosis (MTB). However, the role of NFκB in host defense in humans is not fully understood. We sought to examine the role of NFκB activation in the immune response of human macrophages to MTB. Targeted pharmacologic inhibition of NFκB activation using BAY 11-7082 (BAY, an inhibitor of IκBα kinase) or an adenovirus construct with a dominant-negative IκBα significantly decreased the number of viable intracellular mycobacteria recovered from THP-1 macrophages four and eight days after infection. The results with BAY were confirmed in primary human monocyte-derived macrophages and alveolar macrophages. NFκB inhibition was associated with increased macrophage apoptosis and autophagy, which are well-established killing mechanisms of intracellular MTB. Inhibition of the executioner protease caspase-3 or of the autophagic pathway significantly abrogated the effects of BAY. We conclude that NFκB inhibition decreases viability of intracellular MTB in human macrophages via induction of apoptosis and autophagy. PMID:23634218

  4. Inhibition of nuclear factor-kappa B activation decreases survival of Mycobacterium tuberculosis in human macrophages.

    PubMed

    Bai, Xiyuan; Feldman, Nicole E; Chmura, Kathryn; Ovrutsky, Alida R; Su, Wen-Lin; Griffin, Laura; Pyeon, Dohun; McGibney, Mischa T; Strand, Matthew J; Numata, Mari; Murakami, Seiji; Gaido, Loretta; Honda, Jennifer R; Kinney, William H; Oberley-Deegan, Rebecca E; Voelker, Dennis R; Ordway, Diane J; Chan, Edward D

    2013-01-01

    Nuclear factor-kappa B (NFκB) is a ubiquitous transcription factor that mediates pro-inflammatory responses required for host control of many microbial pathogens; on the other hand, NFκB has been implicated in the pathogenesis of other inflammatory and infectious diseases. Mice with genetic disruption of the p50 subunit of NFκB are more likely to succumb to Mycobacterium tuberculosis (MTB). However, the role of NFκB in host defense in humans is not fully understood. We sought to examine the role of NFκB activation in the immune response of human macrophages to MTB. Targeted pharmacologic inhibition of NFκB activation using BAY 11-7082 (BAY, an inhibitor of IκBα kinase) or an adenovirus construct with a dominant-negative IκBα significantly decreased the number of viable intracellular mycobacteria recovered from THP-1 macrophages four and eight days after infection. The results with BAY were confirmed in primary human monocyte-derived macrophages and alveolar macrophages. NFκB inhibition was associated with increased macrophage apoptosis and autophagy, which are well-established killing mechanisms of intracellular MTB. Inhibition of the executioner protease caspase-3 or of the autophagic pathway significantly abrogated the effects of BAY. We conclude that NFκB inhibition decreases viability of intracellular MTB in human macrophages via induction of apoptosis and autophagy. PMID:23634218

  5. TH1/TH2 paradigm extended: macrophage polarization as an unappreciated pathogen-driven escape mechanism?

    PubMed

    Muraille, Eric; Leo, Oberdan; Moser, Muriel

    2014-01-01

    The classical view of the Th1/Th2 paradigm posits that the pathogen nature, infectious cycle, and persistence represent key parameters controlling the choice of effector mechanisms operating during an immune response. Thus, efficient Th1 responses are triggered by replicating intracellular pathogens, while Th2 responses would control helminth infection and promote tissue repair during the resolution phase of an infectious event. However, this vision does not account for a growing body of data describing how pathogens exploit the polarization of the host immune response to their own benefit. Recently, the study of macrophages has illustrated a novel aspect of this arm race between pathogens and the immune system, and the central role of macrophages in homeostasis, repair and defense of all tissues is now fully appreciated. Like T lymphocytes, macrophages differentiate into distinct effectors including classically (M1) and alternatively (M2) activated macrophages. Interestingly, in addition to represent immune effectors, M1/M2 cells have been shown to represent potential reservoir cells to a wide range of intracellular pathogens. Subversion of macrophage cell metabolism by microbes appears as a recently uncovered immune escape strategy. Upon infection, several microbial agents have been shown to activate host metabolic pathways leading to the production of nutrients necessary to their long-term persistence in host. The purpose of this review is to summarize and discuss the strategies employed by pathogens to manipulate macrophage differentiation, and in particular their basic cell metabolism, to favor their own growth while avoiding immune control. PMID:25505468

  6. Gliotoxin Suppresses Macrophage Immune Function by Subverting Phosphatidylinositol 3,4,5-Trisphosphate Homeostasis

    PubMed Central

    Schlam, Daniel; Canton, Johnathan; Carreño, Marvin; Kopinski, Hannah; Freeman, Spencer A.; Grinstein, Sergio

    2016-01-01

    ABSTRACT Aspergillus fumigatus, an opportunistic fungal pathogen, spreads in the environment by releasing numerous conidia that are capable of reaching the small alveolar airways of mammalian hosts. In otherwise healthy individuals, macrophages are responsible for rapidly phagocytosing and eliminating these conidia, effectively curbing their germination and consequent invasion of pulmonary tissue. However, under some circumstances, the fungus evades phagocyte-mediated immunity and persists in the respiratory tree. Here, we report that A. fumigatus escapes macrophage recognition by strategically targeting phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] metabolism through gliotoxin, a potent immunosuppressive mycotoxin. Time-lapse microscopy revealed that, in response to the toxin, macrophages cease to ruffle, undergo abrupt membrane retraction, and fail to phagocytose large targets effectively. Gliotoxin was found to prevent integrin activation and interfere with actin dynamics, both of which are instrumental for phagocytosis; similar effects were noted in immortalized and primary phagocytes. Detailed studies of the underlying molecular mechanisms of toxicity revealed that inhibition of phagocytosis is attributable to impaired accumulation of PtdIns(3,4,5)P3 and the associated dysregulation of downstream effectors, including Rac and/or Cdc42. Strikingly, in response to the diacylglycerol mimetic phorbol 12-myristate 13-acetate, gliotoxin-treated macrophages reactivate beta integrins, reestablish actin dynamics, and regain phagocytic capacity, despite the overt absence of plasmalemmal PtdIns(3,4,5)P3. Together, our findings identify phosphoinositide metabolism as a critical upstream target of gliotoxin and also indicate that increased diacylglycerol levels can bypass the requirement for PtdIns(3,4,5)P3 signaling during membrane ruffling and phagocytosis. PMID:27048806

  7. Binding and Phagocytosis by Opsonized and Nonopsonized Channel Catfish Macrophages of Viable DsRed-fluorescent-labeled Edwardsiella ictaluri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phagocyte-mediated killing of bacterial pathogens is one of the major defensive mechanisms in fish. The binding, uptake and destruction of recombinant fluorescent protein DsRed transformed Edwardsiella ictaluri by opsonized and nonopsonized channel catfish (Ictalurus punctatus) macrophages was chara...

  8. Antipredator defenses predict diversification rates

    PubMed Central

    Arbuckle, Kevin; Speed, Michael P.

    2015-01-01

    The “escape-and-radiate” hypothesis predicts that antipredator defenses facilitate adaptive radiations by enabling escape from constraints of predation, diversified habitat use, and subsequently speciation. Animals have evolved diverse strategies to reduce the direct costs of predation, including cryptic coloration and behavior, chemical defenses, mimicry, and advertisement of unprofitability (conspicuous warning coloration). Whereas the survival consequences of these alternative defenses for individuals are well-studied, little attention has been given to the macroevolutionary consequences of alternative forms of defense. Here we show, using amphibians as the first, to our knowledge, large-scale empirical test in animals, that there are important macroevolutionary consequences of alternative defenses. However, the escape-and-radiate hypothesis does not adequately describe them, due to its exclusive focus on speciation. We examined how rates of speciation and extinction vary across defensive traits throughout amphibians. Lineages that use chemical defenses show higher rates of speciation as predicted by escape-and-radiate but also show higher rates of extinction compared with those without chemical defense. The effect of chemical defense is a net reduction in diversification compared with lineages without chemical defense. In contrast, acquisition of conspicuous coloration (often used as warning signals or in mimicry) is associated with heightened speciation rates but unchanged extinction rates. We conclude that predictions based on the escape-and-radiate hypothesis must incorporate the effect of traits on both speciation and extinction, which is rarely considered in such studies. Our results also suggest that knowledge of defensive traits could have a bearing on the predictability of extinction, perhaps especially important in globally threatened taxa such as amphibians. PMID:26483488

  9. Antipredator defenses predict diversification rates.

    PubMed

    Arbuckle, Kevin; Speed, Michael P

    2015-11-01

    The "escape-and-radiate" hypothesis predicts that antipredator defenses facilitate adaptive radiations by enabling escape from constraints of predation, diversified habitat use, and subsequently speciation. Animals have evolved diverse strategies to reduce the direct costs of predation, including cryptic coloration and behavior, chemical defenses, mimicry, and advertisement of unprofitability (conspicuous warning coloration). Whereas the survival consequences of these alternative defenses for individuals are well-studied, little attention has been given to the macroevolutionary consequences of alternative forms of defense. Here we show, using amphibians as the first, to our knowledge, large-scale empirical test in animals, that there are important macroevolutionary consequences of alternative defenses. However, the escape-and-radiate hypothesis does not adequately describe them, due to its exclusive focus on speciation. We examined how rates of speciation and extinction vary across defensive traits throughout amphibians. Lineages that use chemical defenses show higher rates of speciation as predicted by escape-and-radiate but also show higher rates of extinction compared with those without chemical defense. The effect of chemical defense is a net reduction in diversification compared with lineages without chemical defense. In contrast, acquisition of conspicuous coloration (often used as warning signals or in mimicry) is associated with heightened speciation rates but unchanged extinction rates. We conclude that predictions based on the escape-and-radiate hypothesis must incorporate the effect of traits on both speciation and extinction, which is rarely considered in such studies. Our results also suggest that knowledge of defensive traits could have a bearing on the predictability of extinction, perhaps especially important in globally threatened taxa such as amphibians. PMID:26483488

  10. Mycobacterium massiliense Induces Macrophage Extracellular Traps with Facilitating Bacterial Growth

    PubMed Central

    Yoon, Yina; Na, Yirang; Kim, Bum-Joon; Seok, Seung Hyeok

    2016-01-01

    Human neutrophils have been known to release neutrophil extracellular traps (NETs), antimicrobial DNA structures capable of capturing and killing microbes. Recently, a similar phenomenon has been reported in macrophages infected with various pathogens. However, a role for macrophages extracellular traps (METs) in host defense responses against Mycobacterium massiliense (M. mass) has yet to be described. In this study, we show that M. mass, a rapid growing mycobacterium (RGM), also induces the release of METs from PMA-differentiated THP-1 cells. Intriguingly, this process is not dependent on NADPH oxidase activity, which regulates NET formation. Instead, M. mass-induced MET formation partially depends on calcium influx and requires phagocytosis of high bacterial load. The METs consist of a DNA backbone embedded with microbicidal proteins such as histone, MPO and elastase. Released METs entrap M. mass and prevent their dissemination, but do not have bactericidal activity. Instead, they result in enhanced bacterial growth. In this regard, METs were considered to provide interaction of M. mass with cells and an environment for bacterial aggregation, which may facilitate mycobacterial survival and growth. In conclusion, our results demonstrate METs as an innate defense response against M. mass infection, and suggest that extracellular traps play a multifaceted role in the interplay between host and bacteria. PMID:27191593

  11. Macrophage-epithelial interactions in pulmonary alveoli.

    PubMed

    Bhattacharya, Jahar; Westphalen, Kristin

    2016-07-01

    Alveolar macrophages have been investigated for years by approaches involving macrophage extraction from the lung by bronchoalveolar lavage, or by cell removal from lung tissue. Since extracted macrophages are studied outside their natural milieu, there is little understanding of the extent to which alveolar macrophages interact with the epithelium, or with one another to generate the lung's innate immune response to pathogen challenge. Here, we review new evidence of macrophage-epithelial interactions in the lung, and we address the emerging understanding that the alveolar epithelium plays an important role in orchestrating the macrophage-driven immune response. PMID:27170185

  12. Elevated CO2 selectively inhibits interleukin-6 and tumor necrosis factor expression and decreases phagocytosis in the macrophage.

    PubMed

    Wang, Naizhen; Gates, Khalilah L; Trejo, Humberto; Favoreto, Silvio; Schleimer, Robert P; Sznajder, Jacob I; Beitel, Greg J; Sporn, Peter H S

    2010-07-01

    Elevated blood and tissue CO(2), or hypercapnia, is common in severe lung disease. Patients with hypercapnia often develop lung infections and have an increased risk of death following pneumonia. To explore whether hypercapnia interferes with host defense, we studied the effects of elevated P(CO2) on macrophage innate immune responses. In differentiated human THP-1 macrophages and human and mouse alveolar macrophages stimulated with lipopolysaccharide (LPS) and other Toll-like receptor ligands, hypercapnia inhibited expression of tumor necrosis factor and interleukin (IL)-6, nuclear factor (NF)-kappaB-dependent cytokines critical for antimicrobial host defense. Inhibition of IL-6 expression by hypercapnia was concentration dependent, rapid, reversible, and independent of extracellular and intracellular acidosis. In contrast, hypercapnia did not down-regulate IL-10 or interferon-beta, which do not require NF-kappaB. Notably, hypercapnia did not affect LPS-induced degradation of IkappaB alpha, nuclear translocation of RelA/p65, or activation of mitogen-activated protein kinases, but it did block IL-6 promoter-driven luciferase activity in mouse RAW 264.7 macrophages. Elevated P(CO2) also decreased phagocytosis of opsonized polystyrene beads and heat-killed bacteria in THP-1 and human alveolar macrophages. By interfering with essential innate immune functions in the macrophage, hypercapnia may cause a previously unrecognized defect in resistance to pulmonary infection in patients with advanced lung disease. PMID:20181940

  13. p-Cresyl sulfate suppresses lipopolysaccharide-induced anti-bacterial immune responses in murine macrophages in vitro.

    PubMed

    Shiba, Takahiro; Makino, Ikuyo; Kawakami, Koji; Kato, Ikuo; Kobayashi, Toshihide; Kaneko, Kimiyuki

    2016-03-14

    p-Cresyl sulfate (pCS) is a known uremic toxin that is metabolized from p-cresol produced by intestinal bacteria. Abnormal accumulation of pCS in the blood is a characteristic of chronic kidney disease (CKD). pCS is suggested to cause immune dysfunction and increase the risk of infectious diseases in CKD patients. In this study, we focused on the effects of pCS on macrophage functions related to host defense. We evaluated the effects of pCS on cytokine production, nitric oxide (NO) production, arginase activity, expression of cell-surface molecules, and phagocytosis in the macrophage-like cell line, RAW264.7. pCS significantly decreased interleukin (IL)-12 p40 production and increased IL-10 production. pCS also decreased NO production, but did not influence arginase activity. pCS suppressed lipopolysaccharide-induced CD40 expression on the cell surface, but did not influence phagocytosis. We further assessed whether the effects of pCS observed in the macrophage-like cell line were consistent in primary macrophages. Similar to RAW264.7 cells, pCS decreased IL-12 p40 and p70 production and increased IL-10 production in primary peritoneal macrophages. These data indicate that pCS suppresses certain macrophage functions that contribute to host defense, and may play a role in CKD-related immune dysfunction. PMID:26784855

  14. Perforin-2 restricts growth of Chlamydia trachomatis in macrophages.

    PubMed

    Fields, K A; McCormack, R; de Armas, L R; Podack, E R

    2013-08-01

    Chlamydia trachomatis is a Gram-negative obligate intracellular bacterium that preferentially infects epithelial cells. Professional phagocytes provide C. trachomatis only a limited ability to survive and are proficient killers of chlamydiae. We present evidence herein that identifies a novel host defense protein, perforin-2, that plays a significant role in the eradication of C. trachomatis during the infection of macrophages. Knockdown of perforin-2 in macrophages did not alter the invasion of host cells but did result in chlamydial growth that closely mirrored that detected in HeLa cells. C trachomatis L2, serovar B, and serovar D and C. muridarum were all equally susceptible to perforin-2-mediated killing. Interestingly, induction of perforin-2 expression in epithelial cells is blocked during productive chlamydial growth, thereby protecting chlamydiae from bactericidal attack. Ectopic expression of perforin-2 in HeLa cells, however, does result in killing. Overall, our data implicate a new innate resistance protein in the control of chlamydial infection and may help explain why the macrophage environment is hostile to chlamydial growth. PMID:23753625

  15. Ambient fine and coarse particle suppression of alveolar macrophage functions.

    PubMed

    Kleinman, M T; Sioutas, C; Chang, M C; Boere, A J F; Cassee, F R

    2003-02-01

    Alveolar macrophages (AM) are part of the innate immunological defense system and are among the first cells to respond to the effects of inhaled particles. Study of macrophage responses to particles is, therefore, relevant to understanding the mechanisms by which inhaled particles can adversely affect health. Size-fractionated ambient particles were collected at traffic-dominated sites in The Netherlands using a mobile high volume slit impactor system. AM were obtained by bronchoalveolar lavage from adult as well as aged rats and were incubated with for 4 h with collected particles at concentrations of 25-1000 pg per cell. Free radical generation by AM was measured with and without stimulation of AM with phorbol myristate acetate (PMA). There were dose-dependent decreases in macrophage production of superoxide radicals as measured by the chemiluminescent method. Coarse particles were more toxic than were fine particles. Suppression of free radical production did not seem to be related to the presence of bioavailable iron or to endotoxin associated with the particles. There were no statistically significant differences related to age or strain of the rats tested. We conclude that in vitro tests using AM is a useful and rapid method for delineating differences in toxicity between environmental samples of size fractionated ambient particles. PMID:12523957

  16. Macrophage tolerance in the gut: It is in the epigenome!

    PubMed

    Schultze, Joachim L

    2016-08-01

    Intestinal macrophages are functionally specialized to phagocytose bacteria, including harmful and invading pathogens, without releasing pro-inflammatory mediators. This unique functional combination guarantees an optimal defense against millions of gut bacteria while at the same time protecting the host from inflammation-related tissue damage. IL-10 seems to be a critical tissue factor involved in this balance and deficiencies in IL-10 in humans and mice have been shown to deteriorate this fine balance, leading to chronic inflammation and diseases such as Crohn's disease. However, the molecular mechanisms downstream of IL-10 are poorly understood. In this issue of European Journal of Immunology, Simon et al. [Eur. J. Immunol. 2016. 46: 1912-1925] demonstrate that the chromatin landscape in gut macrophages derived from mice lacking IL-10 is characteristic of inflammatory macrophages, even in the absence of bacteria. The observed changes of the chromatin landscape represent an important initiating event in chronic intestinal inflammation. These observations are not only an excellent example linking a classical loss-of-function experiment to a molecular mechanism responsible for the induction of chronic inflammation; they also open up new avenues for targeting chromatin and remodeling enzymes in Crohn's disease. PMID:27518699

  17. Optomechanical effects of two-level systems in a back-action evading measurement of micro-mechanical motion

    SciTech Connect

    Suh, J.; Weinstein, A. J.; Schwab, K. C.

    2013-07-29

    We show that the two-level systems (TLS) in lithographic superconducting circuits act as a power-dependent dielectric leading to non-linear responses in a parametrically coupled electromechanical system. Driven TLS shift the microwave resonance frequency and modulate the mechanical resonance through the optical spring effect. By pumping with two tones in a back-action evading measurement, these effects produce a mechanical parametric instability which limits single quadrature imprecision to 1.4 x{sub zp}. The microwave resonator noise is also consistent to a TLS-noise model. These observations suggest design strategies for minimizing TLS effects to improve ground-state cooling and quantum non-demolition measurements of motion.

  18. Optomechanical effects of two-level systems in a back-action evading measurement of micro-mechanical motion

    NASA Astrophysics Data System (ADS)

    Suh, J.; Weinstein, A. J.; Schwab, K. C.

    2013-07-01

    We show that the two-level systems (TLS) in lithographic superconducting circuits act as a power-dependent dielectric leading to non-linear responses in a parametrically coupled electromechanical system. Driven TLS shift the microwave resonance frequency and modulate the mechanical resonance through the optical spring effect. By pumping with two tones in a back-action evading measurement, these effects produce a mechanical parametric instability which limits single quadrature imprecision to 1.4 xzp. The microwave resonator noise is also consistent to a TLS-noise model. These observations suggest design strategies for minimizing TLS effects to improve ground-state cooling and quantum non-demolition measurements of motion.

  19. Self-Defense for Teens

    ERIC Educational Resources Information Center

    Givler, Jill I.

    2005-01-01

    Resources for self-defense training programs have become more popular and available over the last few years. Introducing a self-defense unit as part of a school physical education program is a wonderful way to address a number of psychosocial issues that prevail among teenagers today. The physical skills learned in this type of program allow…

  20. Efficient internalization of mesoporous silica particles of different sizes by primary human macrophages without impairment of macrophage clearance of apoptotic or antibody-opsonized target cells

    SciTech Connect

    Witasp, Erika; Kupferschmidt, Natalia; Bengtsson, Linnea; Hultenby, Kjell; Smedman, Christian; Paulie, Staffan; Garcia-Bennett, Alfonso E.; Fadeel, Bengt

    2009-09-15

    Macrophage recognition and ingestion of apoptotic cell corpses, a process referred to as programmed cell clearance, is of considerable importance for the maintenance of tissue homeostasis and in the resolution of inflammation. Moreover, macrophages are the first line of defense against microorganisms and other foreign materials including particles. However, there is sparse information on the mode of uptake of engineered nanomaterials by primary macrophages. In this study, mesoporous silica particles with cubic pore geometries and covalently fluorescein-grafted particles were synthesized through a novel route, and their interactions with primary human monocyte-derived macrophages were assessed. Efficient and active internalization of mesoporous silica particles of different sizes was observed by transmission electron microscopic and flow cytometric analysis and studies using pharmacological inhibitors suggested that uptake occurred through a process of endocytosis. Moreover, uptake of silica particles was independent of serum factors. The silica particles with very high surface areas due to their porous structure did not impair cell viability or function of macrophages, including the ingestion of different classes of apoptotic or opsonized target cells. The current findings are relevant to the development of mesoporous materials for drug delivery and other biomedical applications.

  1. Jagged1 Instructs Macrophage Differentiation in Leprosy

    PubMed Central

    Teles, Rosane M. B.; Wang, Zhiming; Hong, Patrick; Montoya, Dennis; Krutzik, Stephan; Lee, Seung; Kwon, Ohyun; Modlin, Robert L.; Cruz, Daniel

    2016-01-01

    As circulating monocytes enter the site of disease, the local microenvironment instructs their differentiation into tissue macrophages (MΦ). To identify mechanisms that regulate MΦ differentiation, we studied human leprosy as a model, since M1-type antimicrobial MΦ predominate in lesions in the self-limited form, whereas M2-type phagocytic MΦ are characteristic of the lesions in the progressive form. Using a heterotypic co-culture model, we found that unstimulated endothelial cells (EC) trigger monocytes to become M2 MΦ. However, biochemical screens identified that IFN-γ and two families of small molecules activated EC to induce monocytes to differentiate into M1 MΦ. The gene expression profiles induced in these activated EC, when overlapped with the transcriptomes of human leprosy lesions, identified Jagged1 (JAG1) as a potential regulator of MΦ differentiation. JAG1 protein was preferentially expressed in the lesions from the self-limited form of leprosy, and localized to the vascular endothelium. The ability of activated EC to induce M1 MΦ was JAG1-dependent and the addition of JAG1 to quiescent EC facilitated monocyte differentiation into M1 MΦ with antimicrobial activity against M. leprae. Our findings indicate a potential role for the IFN-γ-JAG1 axis in instructing MΦ differentiation as part of the host defense response at the site of disease in human leprosy. PMID:27532668

  2. Notch signaling regulates expression of Mcl-1 and apoptosis in PPD-treated macrophages

    PubMed Central

    Palaga, Tanapat; Ratanabunyong, Siriluk; Pattarakankul, Thitiporn; Sangphech, Naunpun; Wongchana, Wipawee; Hadae, Yukihiro; Kueanjinda, Patipark

    2013-01-01

    Macrophages are cellular targets for infection by bacteria and viruses. The fate of infected macrophages plays a key role in determining the outcome of the host immune response. Apoptotic cell death of macrophages is considered to be a protective host defense that eliminates pathogens and infected cells. In this study, we investigated the involvement of Notch signaling in regulating apoptosis in macrophages treated with tuberculin purified protein derivative (PPD). Murine bone marrow-derived macrophages (BMMs) treated with PPD or infected with Mycobacterium bovis Bacillus Calmette-Guérin (BCG) induced upregulation of Notch1. This upregulation correlated well with the upregulation of the anti-apoptotic gene mcl-1 both at the transcriptional and translational levels. Decreased levels of Notch1 and Mcl-1 were observed in BMM treated with PPD when a gamma secretase inhibitor (GSI), which inhibits the processing of Notch receptors, was used. Moreover, silencing Notch1 in the macrophage-like cell line RAW264.7 decreased Mcl-1 protein expression, suggesting that Notch1 is critical for Mcl-1 expression in macrophages. A significant increase in apoptotic cells was observed upon treatment of BMM with PPD in the presence of GSI compared to the vehicle-control treated cells. Finally, analysis of the mcl-1 promoter in humans and mice revealed a conserved potential CSL/RBP-Jκ binding site. The association of Notch1 with the mcl-1 promoter was confirmed by chromatin immunoprecipitation. Taken together, these results indicate that Notch1 inhibits apoptosis of macrophages stimulated with PPD by directly controlling the mcl-1 promoter. PMID:23872918

  3. Effect of sulfur dioxide on pulmonary macrophage endocytosis at rest and during exercise

    SciTech Connect

    Skornik, W.A.; Brain, J.D. )

    1990-09-01

    Inhaled SO2 may cause damage by injuring upper airways. To what extent can SO2 also alter pulmonary macrophage function in the parenchyma and what is the impact of exercise We studied the effect of SO2 on pulmonary macrophage endocytosis in resting and in exercising animals by measuring the rates of macrophage endocytosis in situ for 1 h of a test particle of insoluble radioactive colloidal gold (198Au), 1, 24, or 48 h after inhalation exposure to SO2. Resting hamsters exposed for 4 h to 50 ppm SO2 had no significant reduction in macrophage endocytosis compared with air-breathing control hamsters. However, if hamsters were exposed to the same concentration of SO2 while continuously running (40 min at 0.9 km/h), macrophage endocytosis was significantly reduced 1 h after exposure even though the exposure time was only one-sixth as long. Twenty-four hours later, the percentage of gold ingested by pulmonary macrophages remained significantly depressed. By 48 h, the rate had returned to control values. Exercise alone did not affect endocytosis. Hamsters exposed to 50 ppm SO2, with or without exercise, also showed significant reductions in the number of lavaged macrophages. This decrease was greatest and most persistent in the SO2 plus exercise group. These data indicate that even when animals are exposed to water-soluble gases, which are normally removed by the upper airways, exercise can potentiate damage to more peripheral components of the pulmonary defense system such as the macrophage.

  4. The mycotoxin deoxynivalenol inhibits the cell surface expression of activation markers in human macrophages.

    PubMed

    Waché, Yann J; Hbabi-Haddioui, Laila; Guzylack-Piriou, Laurence; Belkhelfa, Haouaria; Roques, Christine; Oswald, Isabelle P

    2009-08-21

    Deoxynivalenol (DON) is the most prevalent trichothecene mycotoxin in crops in Europe and North America. It exhibits several toxic effects including impaired growth and immune dysregulation. Macrophages play pivotal role in the host defense; upon activation, they express several specific cell surface receptors that are important in adhesion and cell signaling. Several studies have demonstrated that DON can affect macrophages, however, very few data are available concerning the effect of DON on human macrophages, and the effect on macrophage cell surface receptors is unknown. In the present study, human blood monocytes, differentiated in vitro into macrophages, were activated with IFN-gamma, in the presence or absence of low concentrations of DON. The expression of CD11c, CD13, CD14, CD18, CD33, CD35, CD54, CD119 and HLA-DP/DQ/DR was analyzed by flow cytometry. As expected, macrophage activation by IFN-gamma upregulated the expression of CD54, CD14, CD119 and HLA-DP/DQ/DR. Incubation with DON decrease the cell surface expression of these activation markers in a dose-dependent manner. When cells were treated with 5muM DON, the mean fluorescence intensity measured for the expression of these receptors was the same as that observed in non-activated macrophages. This inhibitory effect of DON was only observed when the mycotoxin was applied before the activation signal. Taken together, our results suggest that low concentration of DON alter macrophage activation as measured by the expression of cell surface markers. This may have implications for human health when consuming DON contaminated feed. PMID:19549553

  5. Macrophage Heterogeneity in Respiratory Diseases

    PubMed Central

    Boorsma, Carian E.; Draijer, Christina; Melgert, Barbro N.

    2013-01-01

    Macrophages are among the most abundant cells in the respiratory tract, and they can have strikingly different phenotypes within this environment. Our knowledge of the different phenotypes and their functions in the lung is sketchy at best, but they appear to be linked to the protection of gas exchange against microbial threats and excessive tissue responses. Phenotypical changes of macrophages within the lung are found in many respiratory diseases including asthma, chronic obstructive pulmonary disease (COPD), and pulmonary fibrosis. This paper will give an overview of what macrophage phenotypes have been described, what their known functions are, what is known about their presence in the different obstructive and restrictive respiratory diseases (asthma, COPD, pulmonary fibrosis), and how they are thought to contribute to the etiology and resolution of these diseases. PMID:23533311

  6. [Defensive Medicine: Defensive Medicine: Overview of the literature].

    PubMed

    Panella, Massimiliano; Leigheb, Fabrizio; Rinaldi, Carmela; Donnarumma, Chiara; Tozzi, Quinto; Di Stanislao, Francesco

    2015-01-01

    A literature review was performed on the subject of defensive medicine, in order to gather information and evidence for identifying a shared definition of this phenomenon, identify its causes, quantify its frequency and its economic impact.Results show that defensive medicine is primarily the result of medical professionals adapting to the pressure of litigation risks, and whose behaviour is motivated by fear of malpractice claims rather than by the patient's health. Defensive medicine seems to have become a diffuse phenomenon, afflicting all diagnostic-therapeutic areas and some disciplines to a greater degree, and leading to a large waste of human, organizational and economic resources. PMID:26241515

  7. TFEB and TFE3 cooperate in the regulation of the innate immune response in activated macrophages.

    PubMed

    Pastore, Nunzia; Brady, Owen A; Diab, Heba I; Martina, José A; Sun, Lu; Huynh, Tuong; Lim, Jeong-A; Zare, Hossein; Raben, Nina; Ballabio, Andrea; Puertollano, Rosa

    2016-08-01

    The activation of transcription factors is critical to ensure an effective defense against pathogens. In this study we identify a critical and complementary role of the transcription factors TFEB and TFE3 in innate immune response. By using a combination of chromatin immunoprecipitation, CRISPR-Cas9-mediated genome-editing technology, and in vivo models, we determined that TFEB and TFE3 collaborate with each other in activated macrophages and microglia to promote efficient autophagy induction, increased lysosomal biogenesis, and transcriptional upregulation of numerous proinflammatory cytokines. Furthermore, secretion of key mediators of the inflammatory response (CSF2, IL1B, IL2, and IL27), macrophage differentiation (CSF1), and macrophage infiltration and migration to sites of inflammation (CCL2) was significantly reduced in TFEB and TFE3 deficient cells. These new insights provide us with a deeper understanding of the transcriptional regulation of the innate immune response. PMID:27171064

  8. INTERLEUKIN-4- AND INTERLEUKIN-13-MEDIATED ALTERNATIVELY ACTIVATED MACROPHAGES: ROLES IN HOMEOSTASIS AND DISEASE

    PubMed Central

    Van Dyken, Steven J.; Locksley, Richard M.

    2013-01-01

    The macrophage, a versatile cell type prominently involved in host defense and immunity, assumes a distinct state of alternative activation in the context of polarized type 2 immune responses such as allergic inflammation and helminth infection. This alternatively activated phenotype is induced by the canonical type 2 cytokines interleukin (IL)-4 and IL-13, which mediate expression of several characteristic markers along with a dramatic shift in macrophage metabolic pathways that influence surrounding cells and tissues. We discuss recent advances in the understanding of IL-4- and IL-13-mediated alternatively activated macrophages and type 2 immune responses; such advances have led to an expanded appreciation for functions of these cells beyond immunity, including maintenance of physiologic homeostasis and tissue repair. PMID:23298208

  9. Cisplatin stimulates protein tyrosine phosphorylation in macrophages.

    PubMed

    Kumar, R; Shrivastava, A; Sodhi, A

    1995-03-01

    Cisplatin [cis-dichlorodiamine platinum (II)], a potent anti-tumor compound, stimulates immune responses by activating monocyte-macrophages and other cells of the immune system. The mechanism by which cisplatin activates these cells is poorly characterized. Since protein tyrosine phosphorylation appears to be a major intracellular signalling event that mediates cellular responses, we examined whether cisplatin alters tyrosine phosphorylation in macrophages. We found that cisplatin increased tyrosine phosphorylation of several proteins in peritoneal macrophages and in P388D1 and IC-21 macrophage cell lines. Treatment of macrophages with tyrosine kinase inhibitors, genestein and lavendustin A, inhibited cisplatin-stimulated protein tyrosine phosphorylation in macrophages. Macrophages treated with cisplatin also exhibit increased fluorescence with anti-phosphotyrosine-FITC antibody. These data indicate that protein tyrosine phosphorylation plays a role in cisplatin-induced activation of macrophages. PMID:7539662

  10. Origin and Functions of Tissue Macrophages

    PubMed Central

    Epelman, Slava; Lavine, Kory J.; Randolph, Gwendalyn J.

    2015-01-01

    Macrophages are distributed in tissues throughout the body and contribute to both homeostasis and disease. Recently, it has become evident that most adult tissue macrophages originate during embryonic development and not from circulating monocytes. Each tissue has its own composition of embryonically derived and adult-derived macrophages, but it is unclear whether macrophages of distinct origins are functionally interchangeable or have unique roles at steady state. This new understanding also prompts reconsideration of the function of circulating monocytes. Classical Ly6chi monocytes patrol the extravascular space in resting organs, and Ly6clo nonclassical monocytes patrol the vasculature. Inflammation triggers monocytes to differentiate into macrophages, but whether resident and newly recruited macrophages possess similar functions during inflammation is unclear. Here, we define the tools used for identifying the complex origin of tissue macrophages and discuss the relative contributions of tissue niche versus ontological origin to the regulation of macrophage functions during steady state and inflammation. PMID:25035951

  11. Bacteria evade immune recognition via TLR13 and binding of their 23S rRNA by MLS antibiotics by the same mechanisms

    PubMed Central

    Hochrein, Hubertus; Kirschning, Carsten J.

    2013-01-01

    The immune system recognizes pathogens and other danger by means of pattern recognition receptors. Recently, we have demonstrated that the orphan Toll-like receptor 13 (TLR13) senses a defined sequence of the bacterial rRNA and that bacteria use specific mechanisms to evade macrolide lincosamide streptogramin (MLS) antibiotics detection via TLR13. PMID:23802068

  12. HIV-1 assembly in macrophages

    PubMed Central

    2010-01-01

    The molecular mechanisms involved in the assembly of newly synthesized Human Immunodeficiency Virus (HIV) particles are poorly understood. Most of the work on HIV-1 assembly has been performed in T cells in which viral particle budding and assembly take place at the plasma membrane. In contrast, few studies have been performed on macrophages, the other major target of HIV-1. Infected macrophages represent a viral reservoir and probably play a key role in HIV-1 physiopathology. Indeed macrophages retain infectious particles for long periods of time, keeping them protected from anti-viral immune response or drug treatments. Here, we present an overview of what is known about HIV-1 assembly in macrophages as compared to T lymphocytes or cell lines. Early electron microscopy studies suggested that viral assembly takes place at the limiting membrane of an intracellular compartment in macrophages and not at the plasma membrane as in T cells. This was first considered as a late endosomal compartment in which viral budding seems to be similar to the process of vesicle release into multi-vesicular bodies. This view was notably supported by a large body of evidence involving the ESCRT (Endosomal Sorting Complex Required for Transport) machinery in HIV-1 budding, the observation of viral budding profiles in such compartments by immuno-electron microscopy, and the presence of late endosomal markers associated with macrophage-derived virions. However, this model needs to be revisited as recent data indicate that the viral compartment has a neutral pH and can be connected to the plasma membrane via very thin micro-channels. To date, the exact nature and biogenesis of the HIV assembly compartment in macrophages remains elusive. Many cellular proteins potentially involved in the late phases of HIV-1 cycle have been identified; and, recently, the list has grown rapidly with the publication of four independent genome-wide screens. However, their respective roles in infected cells

  13. T cells and macrophages in Trypanosoma brucei-related glomerulopathy.

    PubMed Central

    van Velthuysen, M L; Mayen, A E; van Rooijen, N; Fleuren, G J; de Heer, E; Bruijn, J A

    1994-01-01

    In a previous study, susceptibility for Trypanosoma brucei-related glomerulopathy in mice was shown to be dependent on non-major histocompatibility complex genes. Glomerular disease in this model could not be explained by the production of autoantibodies alone. In order to analyze which part of the defense system, in addition to the B-cell compartment, is involved in the development of this infection-related glomerular disease, groups of athymic (BALB/c rnu/rnu), splenectomized, or macrophage-depleted BALB/c mice were inoculated with T. brucei parasites. Polyclonal B-cell activation, invariably observed in infected BALB/c mice, was absent in BALB/c rnu/rnu mice. Glomerular disease in athymic mice, however, as defined by albuminuria and deposition of immune complexes, was not different from that seen in euthymic infected BALB/c mice. Splenectomy prior to inoculation of parasites led to a decreased incidence of albuminuria in 40% of the animals, whereas splenectomy 21 days after inoculation reduced albuminuria significantly, suggesting a role for spleen cells in the induction of glomerular disease. After macrophage depletion with liposome-encapsulated dichlorodimethylene-diphosphonate, infected BALB/c mice developed significantly higher albuminuria levels for a period up to 2 weeks after depletion. Therefore, it was concluded that the development of T. brucei-related glomerular disease is independent of thymus-matured T cells, while the involvement of macrophages in the development of proteinuria is inhibitory rather than disease inducing. Spleen cells other than thymus-dependent T cells, B cells, and macrophages should be investigated for their role in the pathogenesis of this glomerulopathy. Images PMID:7913696

  14. Macrophage Heterogeneity and Plasticity: Impact of Macrophage Biomarkers on Atherosclerosis

    PubMed Central

    Rojas, Joselyn; Salazar, Juan; Martínez, María Sofía; Palmar, Jim; Bautista, Jordan; Chávez-Castillo, Mervin; Gómez, Alexis; Bermúdez, Valmore

    2015-01-01

    Cardiovascular disease (CVD) is a global epidemic, currently representing the worldwide leading cause of morbidity and mortality. Atherosclerosis is the fundamental pathophysiologic component of CVD, where the immune system plays an essential role. Monocytes and macrophages are key mediators in this aspect: due to their heterogeneity and plasticity, these cells may act as either pro- or anti-inflammatory mediators. Indeed, monocytes may develop heterogeneous functional phenotypes depending on the predominating pro- or anti-inflammatory microenvironment within the lesion, resulting in classic, intermediate, and non-classic monocytes, each with strikingly differing features. Similarly, macrophages may also adopt heterogeneous profiles being mainly M1 and M2, the former showing a proinflammatory profile while the latter demonstrates anti-inflammatory traits; they are further subdivided in several subtypes with more specialized functions. Furthermore, macrophages may display plasticity by dynamically shifting between phenotypes in response to specific signals. Each of these distinct cell profiles is associated with diverse biomarkers which may be exploited for therapeutic intervention, including IL-10, IL-13, PPAR-γ, LXR, NLRP3 inflammasomes, and microRNAs. Direct modulation of the molecular pathways concerning these potential macrophage-related targets represents a promising field for new therapeutic alternatives in atherosclerosis and CVD. PMID:26491604

  15. Directed energy planetary defense

    NASA Astrophysics Data System (ADS)

    Lubin, Philip; Hughes, Gary B.; Bible, Johanna; Bublitz, Jesse; Arriola, Josh; Motta, Caio; Suen, Jon; Johansson, Isabella; Riley, Jordan; Sarvian, Nilou; Clayton-Warwick, Deborah; Wu, Jane; Milich, Andrew; Oleson, Mitch; Pryor, Mark; Krogen, Peter; Kangas, Miikka

    2013-09-01

    Asteroids and comets that cross Earth's orbit pose a credible risk of impact, with potentially severe disturbances to Earth and society. Numerous risk mitigation strategies have been described, most involving dedicated missions to a threatening object. We propose an orbital planetary defense system capable of heating the surface of potentially hazardous objects to the vaporization point as a feasible approach to impact risk mitigation. We call the system DE-STAR for Directed Energy System for Targeting of Asteroids and exploRation. DE-STAR is a modular phased array of kilowatt class lasers powered by photovoltaic's. Modular design allows for incremental development, test, and initial deployment, lowering cost, minimizing risk, and allowing for technological co-development, leading eventually to an orbiting structure that would be developed in stages with both technological and target milestones. The main objective of DE-STAR is to use the focused directed energy to raise the surface spot temperature to ~3,000K, allowing direct vaporization of all known substances. In the process of heating the surface ejecting evaporated material a large reaction force would alter the asteroid's orbit. The baseline system is a DE-STAR 3 or 4 (1-10km array) depending on the degree of protection desired. A DE-STAR 4 allows for asteroid engagement starting beyond 1AU with a spot temperature sufficient to completely evaporate up to 500-m diameter asteroids in one year. Small asteroids and comets can be diverted/evaporated with a DESTAR 2 (100m) while space debris is vaporized with a DE-STAR 1 (10m).

  16. Ubiquitination by SAG regulates macrophage survival/death and immune response during infection

    PubMed Central

    Chang, S C; Ding, J L

    2014-01-01

    The checkpoint between the life and death of macrophages is crucial for the host's frontline immune defense during acute phase infection. However, the mechanism as to how the immune cell equilibrates between apoptosis and immune response is unclear. Using in vitro and ex vivo approaches, we showed that macrophage survival is synchronized by SAG (sensitive to apoptosis gene), which is a key member of the ubiquitin–proteasome system (UPS). When challenged by pathogen-associated molecular patterns (PAMPs), we observed a reciprocal expression profile of pro- and antiapoptotic factors in macrophages. However, SAG knockdown disrupted this balance. Further analysis revealed that ubiquitination of Bax and SARM (sterile α- and HEAT/armadillo-motif-containing protein) by SAG-UPS confers survival advantage to infected macrophages. SAG knockdown caused the accumulation of proapoptotic Bax and SARM, imbalance of Bcl-2/Bax in the mitochondria, induction of cytosolic cytochrome c and activation of caspase-9 and -3, all of which led to disequilibrium between life and death of macrophages. In contrast, SAG-overexpressing macrophages challenged with PAMPs exhibited upregulation of protumorigenic cytokines (IL-1β, IL-6 and TNF-α), and downregulation of antitumorigenic cytokine (IL-12p40) and anti-inflammatory cytokine (IL-10). This suggests that SAG-dependent UPS is a key switch between immune defense and apoptosis or immune overactivation and tumorigenesis. Altogether, our results indicate that SAG-UPS facilitates a timely and appropriate level of immune response, prompting future development of potential immunomodulators of SAG-UPS. PMID:24786833

  17. Ubiquitination by SAG regulates macrophage survival/death and immune response during infection.

    PubMed

    Chang, S C; Ding, J L

    2014-09-01

    The checkpoint between the life and death of macrophages is crucial for the host's frontline immune defense during acute phase infection. However, the mechanism as to how the immune cell equilibrates between apoptosis and immune response is unclear. Using in vitro and ex vivo approaches, we showed that macrophage survival is synchronized by SAG (sensitive to apoptosis gene), which is a key member of the ubiquitin-proteasome system (UPS). When challenged by pathogen-associated molecular patterns (PAMPs), we observed a reciprocal expression profile of pro- and antiapoptotic factors in macrophages. However, SAG knockdown disrupted this balance. Further analysis revealed that ubiquitination of Bax and SARM (sterile α- and HEAT/armadillo-motif-containing protein) by SAG-UPS confers survival advantage to infected macrophages. SAG knockdown caused the accumulation of proapoptotic Bax and SARM, imbalance of Bcl-2/Bax in the mitochondria, induction of cytosolic cytochrome c and activation of caspase-9 and -3, all of which led to disequilibrium between life and death of macrophages. In contrast, SAG-overexpressing macrophages challenged with PAMPs exhibited upregulation of protumorigenic cytokines (IL-1β, IL-6 and TNF-α), and downregulation of antitumorigenic cytokine (IL-12p40) and anti-inflammatory cytokine (IL-10). This suggests that SAG-dependent UPS is a key switch between immune defense and apoptosis or immune overactivation and tumorigenesis. Altogether, our results indicate that SAG-UPS facilitates a timely and appropriate level of immune response, prompting future development of potential immunomodulators of SAG-UPS. PMID:24786833

  18. microRNA-146a promotes mycobacterial survival in macrophages through suppressing nitric oxide production

    PubMed Central

    Li, Miao; Wang, Jinli; Fang, Yimin; Gong, Sitang; Li, Meiyu; Wu, Minhao; Lai, Xiaomin; Zeng, Gucheng; Wang, Yi; Yang, Kun; Huang, Xi

    2016-01-01

    Macrophages play a crucial role in host innate anti-mycobacterial defense, which is tightly regulated by multiple factors, including microRNAs. Our previous study showed that a panel of microRNAs was markedly up-regulated in macrophages upon mycobacterial infection. Here, we investigated the biological function of miR-146a during mycobacterial infection. miR-146a expression was induced both in vitro and in vivo after Mycobacterium bovis BCG infection. The inducible miR-146a could suppress the inducible nitric oxide (NO) synthase (iNOS) expression and NO generation, thus promoting mycobacterial survival in macrophages. Inhibition of endogenous miR-146a increased NO production and mycobacterial clearance. Moreover, miR-146a attenuated the activation of nuclear factor κB and mitogen-activated protein kinases signaling pathways during BCG infection, which in turn repressed iNOS expression. Mechanistically, miR-146a directly targeted tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6) at post-transcriptional level. Silencing TRAF6 decreased iNOS expression and NO production in BCG-infected macrophages, while overexpression of TRAF6 reversed miR-146a-mediated inhibition of NO production and clearance of mycobacteria. Therefore, we demonstrated a novel role of miR-146a in the modulation of host defense against mycobacterial infection by repressing NO production via targeting TRAF6, which may provide a promising therapeutic target for tuberculosis. PMID:27025258

  19. Macrophage dysfunction and susceptibility to pulmonary Pseudomonas aeruginosa infection in surfactant protein C-deficient mice.

    PubMed

    Glasser, Stephan W; Senft, Albert P; Whitsett, Jeffrey A; Maxfield, Melissa D; Ross, Gary F; Richardson, Theresa R; Prows, Daniel R; Xu, Yan; Korfhagen, Thomas R

    2008-07-01

    To determine the role of surfactant protein C (SP-C) in host defense, SP-C-deficient (Sftpc-/-) mice were infected with the pulmonary pathogen Pseudomonas aeruginosa by intratracheal injection. Survival of young, postnatal day 14 Sftpc-/- mice was decreased in comparison to Sftpc+/+ mice. The sensitivity to Pseudomonas bacteria was specific to the 129S6 strain of Sftpc-/- mice, a strain that spontaneously develops interstitial lung disease-like lung pathology with age. Pulmonary bacterial load and leukocyte infiltration were increased in the lungs of Sftpc-/- mice 24 h after infection. Early influx of polymorphonuclear leukocytes in the lungs of uninfected newborn Sftpc-/- mice relative to Sftpc+/+ mice indicate that the lack of SP-C promotes proinflammatory responses in the lung. Mucin expression, as indicated by Alcian blue staining, was increased in the airways of Sftpc-/- mice following infection. Phagocytic activity of alveolar macrophages from Sftpc-/- mice was reduced. The uptake of fluorescent beads in vitro and the number of bacteria phagocytosed by alveolar macrophages in vivo was decreased in the Sftpc-/- mice. Alveolar macrophages from Sftpc-/- mice expressed markers of alternative activation that are associated with diminished pathogen response and advancing pulmonary fibrosis. These findings implicate SP-C as a modifier of alveolar homeostasis. SP-C plays an important role in innate host defense of the lung, enhancing macrophage-mediated Pseudomonas phagocytosis, clearance and limiting pulmonary inflammatory responses. PMID:18566429

  20. Subterfuge and sabotage: evasion of host innate defenses by invasive gram-positive bacterial pathogens.

    PubMed

    Okumura, Cheryl Y M; Nizet, Victor

    2014-01-01

    The development of a severe invasive bacterial infection in an otherwise healthy individual is one of the most striking and fascinating aspects of human medicine. A small cadre of gram-positive pathogens of the genera Streptococcus and Staphylococcus stand out for their unique invasive disease potential and sophisticated ability to counteract the multifaceted components of human innate defense. This review illustrates how these leading human disease agents evade host complement deposition and activation, impede phagocyte recruitment and activation, resist the microbicidal activities of host antimicrobial peptides and reactive oxygen species, escape neutrophil extracellular traps, and promote and accelerate phagocyte cell death through the action of pore-forming cytolysins. Understanding the molecular basis of bacterial innate immune resistance can open new avenues for therapeutic intervention geared to disabling specific virulence factors and resensitizing the pathogen to host innate immune clearance. PMID:25002085

  1. Direct measurement of oxidative and nitrosative stress dynamics in Salmonella inside macrophages.

    PubMed

    van der Heijden, Joris; Bosman, Else S; Reynolds, Lisa A; Finlay, B Brett

    2015-01-13

    Many significant bacterial pathogens have evolved virulence mechanisms to evade degradation and exposure to reactive oxygen (ROS) and reactive nitrogen species (RNS), allowing them to survive and replicate inside their hosts. Due to the highly reactive and short-lived nature of ROS and RNS, combined with limitations of conventional detection agents, the mechanisms underlying these evasion strategies remain poorly understood. In this study, we describe a system that uses redox-sensitive GFP to nondisruptively measure real-time fluctuations in the intrabacterial redox environment. Using this system coupled with high-throughput microscopy, we report the intrabacterial redox dynamics of Salmonella enterica Typhimurium (S. Typhimurium) residing inside macrophages. We found that the bacterial SPI-2 type III secretion system is required for ROS evasion strategies and this evasion relies on an intact Salmonella-containing vacuole (SCV) within which the bacteria reside during infection. Additionally, we found that cytosolic bacteria that escape the SCV experience increased redox stress in human and murine macrophages. These results highlight the existence of specialized evasion strategies used by intracellular pathogens that either reside inside a vacuole or "escape" into the cytosol. Taken together, the use of redox-sensitive GFP inside Salmonella significantly advances our understanding of ROS and RNS evasion strategies during infection. This technology can also be applied to measuring bacterial oxidative and nitrosative stress dynamics under different conditions in a wide variety of bacteria. PMID:25548165

  2. Response to stimulation with recombinant cytokines and synthesis of cytokines by murine intestinal macrophages infected with the Mycobacterium avium complex.

    PubMed Central

    Hsu, N; Young, L S; Bermudez, L E

    1995-01-01

    Current evidence suggests that the gut is the chief portal of entry for organisms of the Mycobacterium avium complex (MAC) in AIDS patients. Bacterial invasion of intestinal mucosa presumably occurs through epithelial cells, and M cells in the Peyer's patches, where the bacteria have contact with immunocompetent cells such as macrophages and T and B lymphocytes. As mucosal macrophages are probably the first line of defense against MAC, we examined their ability to inhibit intracellular growth of MAC when properly stimulated. Mouse intestinal macrophages were purified, infected with MAC 101, serovar 1, and MAC 86-2686, serovar 16, and subsequently stimulated with recombinant tumor necrosis factor alpha (TNF-alpha), gamma interferon (IFN-gamma), granulocyte-macrophage colony-stimulating factor (GM-CSF), or macrophage colony-stimulating factor (M-CSF). Viable intracellular bacteria were quantitated at 24 h after infection and again after 4 days of infection. Stimulation with TNF-alpha, IFN-gamma, and GM-CSF, but not M-CSF, was associated with mycobacteriostatic and/or mycobactericidal activity in macrophages. Treatment with 10(3) U of TNF-alpha, GM-CSF, and IFN-gamma per ml at 24 h prior to infection with MAC resulted in a significant enhancement in killing of MAC at 4 days after infection, compared with that observed for macrophages exposed to cytokines after infection. When stimulated with lipopolysaccharide or live MAC, intestinal macrophages had produced significantly less TNF-alpha and transforming growth factor beta than had splenic and peritoneal macrophages, although the levels of production of interleukin 6 and interleukin 10 among the three populations of cells were similar. Intestinal macrophages can be stimulated with cytokines to inhibit the intracellular growth of MAC, but they have differentiated abilities to produce cytokines which can modulate the anti-MAC immune response. PMID:7822018

  3. Toll-like receptor 9 modulates macrophage antifungal effector function during innate recognition of Candida albicans and Saccharomyces cerevisiae.

    PubMed

    Kasperkovitz, Pia V; Khan, Nida S; Tam, Jenny M; Mansour, Michael K; Davids, Peter J; Vyas, Jatin M

    2011-12-01

    Phagocytic responses are critical for effective host defense against opportunistic fungal pathogens. Macrophages sample the phagosomal content and orchestrate the innate immune response. Toll-like receptor 9 (TLR9) recognizes unmethylated CpG DNA and is activated by fungal DNA. Here we demonstrate that specific triggering of TLR9 recruitment to the macrophage phagosomal membrane is a conserved feature of fungi of distinct phylogenetic origins, including Candida albicans, Saccharomyces cerevisiae, Malassezia furfur, and Cryptococcus neoformans. The capacity to trigger phagosomal TLR9 recruitment was not affected by a loss of fungal viability or cell wall integrity. TLR9 deficiency has been linked to increased resistance to murine candidiasis and to restriction of fungal growth in vivo. Macrophages lacking TLR9 demonstrate a comparable capacity for phagocytosis and normal phagosomal maturation compared to wild-type macrophages. We now show that TLR9 deficiency increases macrophage tumor necrosis factor alpha (TNF-α) production in response to C. albicans and S. cerevisiae, independent of yeast viability. The increase in TNF-α production was reversible by functional complementation of the TLR9 gene, confirming that TLR9 was responsible for negative modulation of the cytokine response. Consistently, TLR9 deficiency enhanced the macrophage effector response by increasing macrophage nitric oxide production. Moreover, microbicidal activity against C. albicans and S. cerevisiae was more efficient in TLR9 knockout (TLR9KO) macrophages than in wild-type macrophages. In conclusion, our data demonstrate that TLR9 is compartmentalized selectively to fungal phagosomes and negatively modulates macrophage antifungal effector functions. Our data support a model in which orchestration of antifungal innate immunity involves a complex interplay of fungal ligand combinations, host cell machinery rearrangements, and TLR cooperation and antagonism. PMID:21947771

  4. The effect of chronic exposure to tobacco smoke on the antibacterial defenses of the lung.

    PubMed

    Huber, G L; Pochay, V E; Mahajan, V K; McCarthy, C R; Hinds, W C; Davies, P; Drath, D B; Sornberger, G C

    1977-01-01

    To evaluate the effects of cigarette smoking on the host defenses of the lung, male CD rats were exposed to fresh whole smoke for up to 60 consecutive days. Intrapulmonary deposition of smoke and animal exposure levels, quantified with decachlorobiphenyl and other smoke tracers, indicated a daily cigarette exposure equivalent to approximately a pack and a half per day in man. Pulmonary alveolar macrophage function in situ was quantified by the inactivation of an aerosolized challenge of Staphylococcus aureus six hours after inoculation. Controls (n=120) inactivated 88.8+/-0.64% of the staphylococci. Exposure to whole smoke did not impair intrapulmonary antistaphylococcal defenses, with inactivation rates of 89.8+/-0.97% (n=49) and 89.1+/-0.46% (n=74) at 30 and 60 days, respectively. Inactivation distribution frequency analysis in controls revealed that 7% of animals had inactivation values greater than two standard deviations from the mean. With prolonged exposure mean with less skewing towards the abnormal. Alveolar macrophages harvested from smoked animals were comparable in viability and in vitro antistaphylococcal activity to controls, appeared to be metabolically activated and had specific stereologic ultrastructural alterations. These studies indicate that chronic exposure to tobacco smoke does not impair, and in fact may stimulate, the host defenses of the lung, as evaluated by in vivo and in vitro pulmonary alveolar macrophage function. PMID:843645

  5. Changes in the proteomic profile during the differential polarization status of the human monocyte-derived macrophage THP-1 cell line.

    PubMed

    Zhang, Fan; Liu, Hao; Jiang, Guanmin; Wang, Hongsheng; Wang, Xianfeng; Wang, Hao; Fang, Rui; Cai, Shaohui; Du, Jun

    2015-02-01

    Macrophages are heterogeneous and plastic populations that are an essential component of inflammation and host defense. To understand how macrophages respond to cytokine signals, we used 2DE to identify protein profiles in macrophages stimulated with interleukin 4 (M2) and those stimulated with lipopolysaccharide and interferon γ (M1). In total, 32 differentially expressed proteins in THP-1 cells were identified by MALDI-TOF MS/MS analysis. The different proteins were mainly involved in cellular structure, protein metabolism, stress response, oxidative response, and nitric oxide production during macrophage polarization. In particular, proteins playing important roles in production of nitric oxide (NO) were downregulated in M2 macrophages. Many antioxidant and heat shock proteins, which are related to oxidative response, were upregulated in M2 macrophages. More importantly, a remarkable decrease in intracellular ROS and NO production were detected in M2 macrophages. Our results provide a proteomic profile of differentially polarized macrophages and validate the function of the identified proteins, which may indicate possible mechanism of macrophage polarization process. PMID:25411139

  6. Regulation of intrinsic apoptosis in cycloheximide-treated macrophages by the Sichuan human strain of Chinese Leishmania isolates.

    PubMed

    Zeng, Jin; Chen, Qi-Wei; Yu, Ze-Ying; Zhang, Jun-Rong; Chen, Da-Li; Song, Chen; Luo, Jie; Zhang, Chen; Wang, Shun-Li; Chen, Jian-Ping

    2016-01-01

    Leishmania spp. are able to survive and proliferate inside mammals' mononuclear phagocytes, causing Leishmaniasis. Previous studies have noted that the regulation of apoptosis in host cells by these parasites may contribute to their ability to evade the immune system. However, current results remain unclear about whether the parasites can promote or delay the apoptotic process in host cells, because the regulatory effect of Leishmania was assumed to be strain-, species- and even infection time-dependent. The aim of this study was to investigate whether the Sichuan isolates of Chinese Leishmania (SC10H2) can alter the process of intrinsic apoptosis induced by cycloheximide in different types of macrophage cell lines and to determine in which steps of the signaling pathway the parasites were involved. Human THP-1 and mouse RAW264.7 macrophages were infected by SC10H2 promastigotes followed by cycloheximide stimulation to assess the alteration of intrinsic apoptosis in these cells. The results indicated that SC10H2 infection of human THP-1 macrophages could promote the initiation of intrinsic apoptosis, but completely opposite results were found in mouse RAW264.7 macrophages. Nevertheless, the expression of Bcl-2 and the DNA fragmentation rates were not altered by SC10H2 infection in the cell lines used in the experiments. This study suggests that SC10H2 promastigote infection is able to promote and delay the transduction of early apoptotic signals induced by cycloheximide in THP-1 and RAW264.7 macrophages, revealing that the regulation of intrinsic apoptosis in host cells by SC10H2 in vitro occurs in a host cell-dependent manner. The data from this study might play a significant role in further understanding the relationship between Leishmania and different host cells. PMID:26482137

  7. Localization of major histocompatibility complex class II molecules in phagolysosomes of murine macrophages infected with Leishmania amazonensis.

    PubMed Central

    Antoine, J C; Jouanne, C; Lang, T; Prina, E; de Chastellier, C; Frehel, C

    1991-01-01

    Leishmania-infected macrophages are potential antigen-presenting cells for CD4+ T lymphocytes, which recognize parasite antigens bound to major histocompatibility complex class II molecules (Ia). However, the intracellular sites where Ia and antigens may interact are far from clear, since parasites grow within the modified lysosomal compartment of the host cell, whereas Ia molecules seem to be targeted to endosomes. To address this question, the expression and fate of Ia molecules were studied by immunocytochemistry in Leishmania amazonensis-infected murine macrophages stimulated with gamma interferon. In uninfected macrophages, Ia molecules were localized on the plasma membrane and in perinuclear vesicles, but they underwent a dramatic redistribution after infection, since most of the intracellular staining was then associated with the periphery of the parasitophorous vacuoles (p.v.) and quite often polarized towards amastigote-binding sites. The Ii invariant chain, which is transiently associated with Ia during their intracellular transport, although well expressed in infected macrophages, apparently did not reach the p.v. Similar findings were observed with macrophages from mice either resistant or highly susceptible to Leishmania infection. In order to determine the origin of p.v.-associated Ia, the fate of plasma membrane, endosomal, and lysosomal markers, detected with specific antibodies, was determined after infection. At 48 h after infection, p.v. was found to exhibit a membrane composition typical of mature lysosomes. Overall, these data suggest that (i) Ia located in p.v. originate from secondary lysosomes involved in the biogenesis of this compartment or circulate in several endocytic organelles, including lysosomes and (ii) p.v. could play a role in antigen processing and presentation. Alternatively, the presence of high amounts of Ia in p.v. could be due to a Leishmania-induced mechanism by means of which this organism may evade the immune response

  8. Host defenses trigger salmonella's arsenal.

    PubMed

    Keestra, A Marijke; Bäumler, Andreas J

    2011-03-17

    Salmonella survives in macrophages by using a molecular syringe to deliver proteins into the host-cell cytosol where they manipulate phagocyte physiology. Arpaia and colleagues (Arpaia et al., 2011) show that deployment of this virulence factor is triggered by the very responses that are intended to confer host resistance. PMID:21402352

  9. Modulating macrophage response to biomaterials

    NASA Astrophysics Data System (ADS)

    Zaveri, Toral

    Macrophages recruited to the site of biomaterial implantation are the primary mediators of the chronic foreign body response to implanted materials. Since foreign body response limits performance and functional life of numerous implanted biomaterials/medical devices, various approaches have been investigated to modulate macrophage interactions with biomaterial surfaces to mitigate this response. In this work we have explored two independent approaches to modulate the macrophage inflammatory response to biomaterials. The first approach targets surface integrins, cell surface receptors that mediate cell adhesion to biomaterials through adhesive proteins spontaneously adsorbed on biomaterial surfaces. The second approach involves surface modification of biomaterials using nanotopographic features since nanotopography has been reported to modulate cell adhesion and viability in a cell type-dependent manner. More specifically, Zinc Oxide (ZnO) nanorod surface was investigated for its role in modulating macrophage adhesion and survival in vitro and foreign body response in vivo. For the first approach, we have investigated the role of integrin Mac-1 and RGD-binding integrins in the in-vivo osteolysis response and macrophage inflammatory processes of phagocytosis as well as inflammatory cytokine secretion in response to particulate biomaterials. We have also investigated the in vivo foreign body response (FBR) to subcutaneously implanted biomaterials by evaluating the thickness of fibrous capsule formed around the implants after 2 weeks of implantation. The role of Mac-1 integrin was isolated using a Mac-1 KO mouse and comparing it to a WT control. The role of RGD binding integrins in FBR was investigated by coating the implanted biomaterial with ELVAX(TM) polymer loaded with Echistatin which contains the RGD sequence. For the in-vivo osteolysis study and to study the in-vitro macrophage response to particulate biomaterials, we used the RGD peptide encapsulated in ELVAX

  10. Antimicrobial proteins of murine macrophages.

    PubMed Central

    Hiemstra, P S; Eisenhauer, P B; Harwig, S S; van den Barselaar, M T; van Furth, R; Lehrer, R I

    1993-01-01

    Three murine microbicidal proteins (MUMPs) were purified from cells of the murine macrophage cell line RAW264.7 that had been activated by gamma interferon. Similar proteins were also present in nonactivated RAW264.7 cells, in cells of the murine macrophage cell line J774A.1, and in resident and activated murine peritoneal macrophages. MUMP-1, MUMP-2, and MUMP-3 killed Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Mycobacterium fortuitum, and Cryptococcus neoformans in vitro. MUMP-1 resembled an H1 histone but was unusual because its N-terminal residue (serine) was not N acetylated. Although MUMP-2 was N terminally blocked, its high lysine/arginine ratio and its reactivity with an antibody to H1 histones suggested that it also belonged to the H1 histone family. MUMP-3 was identical to histone H2B in 30 of 30 amino-terminal residues. Although the antimicrobial properties of histones have been recognized for decades, this is the first evidence that such proteins may endow the lysosomal apparatus of macrophages with nonoxidative antimicrobial potential. Other MUMPs, including some with a more restricted antimicrobial spectrum and one that appeared to be induced in RAW264.7 cells after gamma interferon stimulation, were noted but remain to be characterized. Images PMID:8514411

  11. Defenseive Structuring and Environmental Stress

    ERIC Educational Resources Information Center

    Siegel, Bernard J.

    1970-01-01

    This essay explores a kind of adaptation, referred to as defenseive structuring, that recurs with great regularity among groups that perceive themselves as exposed to environmental stress of long duration with which they cannot cope directly and aggressively." (Author)

  12. DEFENSE MEDICAL SURVEILLANCE SYSTEM (DMSS)

    EPA Science Inventory

    AMSA operates the Defense Medical Surveillance System (DMSS), an executive information system whose database contains up-to-date and historical data on diseases and medical events (e.g., hospitalizations, ambulatory visits, reportable diseases, HIV tests, acute respiratory diseas...

  13. Strategic Defense Initiative - an overview

    SciTech Connect

    Abrahamson, J.A.

    1985-01-01

    A general framework for developing the concept and implementing options for strategic ballistic missile defense systems is emerging. The objective of the Strategic Defense Initiative (SDI) program is to conduct research on those technologies for defensive system which could intercept ballistic missiles after they have been launched and prevent them from hitting their targets. Its goal is to acquire the technical knowledge as a basis for a later decision on deployment, not a program for deployment or star wars. Abrahamson reviews the basic technological questions facing researchers, outlines the multi-layered defense possibilities and summarizes the status of technology to date. He argues for a continuity of resources to conduct the program. 4 figures.

  14. Interaction of the core fragments of the LL-37 host defense peptide with actin

    PubMed Central

    Sol, Asaf; Wang, Guangshun; Blotnick, Edna; Golla, Radha; Muhlrad, Andras

    2015-01-01

    Host defense peptides are effector molecules of the innate immunity that possess antimicrobial and health-promoting properties. Due to their potential therapeutic activities, host defense peptides are being explored as alternatives for antibiotics. The human LL-37 and its shorter, cost-effective, bactericidal core peptide derivates have been suggested for their therapeutic potential. Bacteria evade host defense peptides by proteolytic inactivation. Actin released from necrotized cells and abundant in infected sites was shown to bind and protect LL-37 from microbial proteolytic degradation, and to enable the peptide’s antimicrobial action despite the presence of the proteases. Here, we characterized the interactions of the 10–13 residues long LL-37 core peptides with actin. We show that the LL-37 core peptides associate with actin with a lower affinity than that of LL-37. Their association with actin, which is very ionic strength sensitive, is mainly based on electrostatic interactions. Likewise, the antimicrobial activity against Escherichia coli of the minimal antimicrobial peptide KR-12 but not FK-13 nor LL-37 is also very sensitive to salts. In addition, the antimicrobial activity of the FK-13 core peptide is protected by actin against the tested bacterial proteases in a similar manner to that of LL-37, supporting its potential for therapeutic use. PMID:26726303

  15. Macrophage Diversity Enhances Tumor Progression and Metastasis

    PubMed Central

    Qian, Binzhi; Pollard, Jeffrey W.

    2016-01-01

    There is persuasive clinical and experimental evidence that macrophages promote cancer initiation and malignant progression. During tumor initiation they create an inflammatory environment that is mutagenic and which promotes growth. As tumors progress to malignancy, macrophages stimulate angiogenesis, enhance tumor cell migration, invasion, and suppress anti-tumor immunity. At metastatic sites macrophages prepare the target tissue for arrival of tumor cells and then a different subpopulation of macrophages promotes tumor cell extravasation, survival, and subsequent growth. Specialized subpopulations of macrophages may represent important new therapeutic targets. PMID:20371344

  16. The journey from stem cell to macrophage

    PubMed Central

    Pittet, Mikael J.; Nahrendorf, Matthias; Swirski, Filip K.

    2014-01-01

    Essential protectors against infection and injury, macrophages can also contribute to many common and fatal diseases. Here we discuss the mechanisms that control different types of macrophage activities in mice. We follow the cells’ maturational pathways over time and space, and elaborate on events that influence the type of macrophage eventually settling a particular destination. The nature of the precursor cells, developmental niches, tissues, environmental cues, and other connecting processes appear to contribute to the identity of macrophage type. Together, the spatial and developmental relationships of macrophages comprise a topo-ontogenic map that can guide our understanding of their biology. PMID:24673186

  17. Strategic defense initiative: critical issues

    SciTech Connect

    Nuckolls, J.H.

    1985-06-01

    The objectives of the Strategic Defense Initiative (SDI) as outlined by President Reagan are discussed. The principal objective for SDI is as a defense against ballistic missiles. Soviet objections and a summary of US-USSR dialogue on the subject are reviewed. Most US studies have been critical of SDI. Four critical issues are addressed in depth: are defense weapons technologically feasible which have high economic leverage relative to offensive ballistic missiles; would the defense feasibility and leverage be degraded or enhanced in the technological race between weapons innovation and countermeasures; could stability be achieved during and after the transition to the defense dominated world envisioned by SDI proponents; would the deployment of high leverage defensive weapons increase or decrease the security of NATO Europe, and the probability of major conventional or nuclear wars. The issue of SDI may lead to a paradox that contains the seeds of catastrophe. The author concludes by warning that nuclear disarmament may eliminate the highly successful deterrent mechanism for avoiding another major world war. In a world made safe for major conventional wars by the apparent ''elimination'' of nuclear weapons, the leaders in a conventional World War III - involving unimaginable suffering, hatred, terror, and death - would be strongly motivated to introduce nuclear weapons in the crucial decisive battles. Even if diplomacy could ''eliminate'' nuclear weapons, man's knowledge of nuclear weapons can never be eliminated. The paradox is the attempt to eliminate nuclear weapons may maximize the probability of their use. (DMC)

  18. Macrophage Polarization during Murine Lyme Borreliosis

    PubMed Central

    Lasky, Carrie E.; Olson, Rachel M.

    2015-01-01

    Infection of C3H mice with Borrelia burgdorferi, the causative agent of Lyme disease, reliably produces an infectious arthritis and carditis that peak around 3 weeks postinfection and then spontaneously resolve. Macrophage polarization has been suggested to drive inflammation, the clearance of bacteria, and tissue repair and resolution in a variety of infectious disease models. During Lyme disease it is clear that macrophages are capable of clearing Borrelia spirochetes and exhausted neutrophils; however, the role of macrophage phenotype in disease development or resolution has not been studied. Using classical (NOS2) and alternative (CD206) macrophage subset-specific markers, we determined the phenotype of F4/80+ macrophages within the joints and heart throughout the infection time course. Within the joint, CD206+ macrophages dominated throughout the course of infection, and NOS2+ macrophage numbers became elevated only during the peak of inflammation. We also found dual NOS2+ CD206+ macrophages which increased during resolution. In contrast to findings for the ankle joints, numbers of NOS2+ and CD206+ macrophages in the heart were similar at the peak of inflammation. 5-Lipoxygenase-deficient (5-LOX−/−) mice, which display a failure of Lyme arthritis resolution, recruited fewer F4/80+ cells to the infected joints and heart, but macrophage subset populations were unchanged. These results highlight differences in the inflammatory infiltrates during Lyme arthritis and carditis and demonstrate the coexistence of multiple macrophage subsets within a single inflammatory site. PMID:25870230

  19. Macrophages and cellular immunity in Drosophila melanogaster.

    PubMed

    Gold, Katrina S; Brückner, Katja

    2015-12-01

    The invertebrate Drosophila melanogaster has been a powerful model for understanding blood cell development and immunity. Drosophila is a holometabolous insect, which transitions through a series of life stages from embryo, larva and pupa to adulthood. In spite of this, remarkable parallels exist between Drosophila and vertebrate macrophages, both in terms of development and function. More than 90% of Drosophila blood cells (hemocytes) are macrophages (plasmatocytes), making this highly tractable genetic system attractive for studying a variety of questions in macrophage biology. In vertebrates, recent findings revealed that macrophages have two independent origins: self-renewing macrophages, which reside and proliferate in local microenvironments in a variety of tissues, and macrophages of the monocyte lineage, which derive from hematopoietic stem or progenitor cells. Like vertebrates, Drosophila possesses two macrophage lineages with a conserved dual ontogeny. These parallels allow us to take advantage of the Drosophila model when investigating macrophage lineage specification, maintenance and amplification, and the induction of macrophages and their progenitors by local microenvironments and systemic cues. Beyond macrophage development, Drosophila further serves as a paradigm for understanding the mechanisms underlying macrophage function and cellular immunity in infection, tissue homeostasis and cancer, throughout development and adult life. PMID:27117654

  20. Inhibiting macrophage proliferation suppresses atherosclerotic plaque inflammation

    PubMed Central

    Tang, Jun; Lobatto, Mark E.; Hassing, Laurien; van der Staay, Susanne; van Rijs, Sarian M.; Calcagno, Claudia; Braza, Mounia S.; Baxter, Samantha; Fay, Francois; Sanchez-Gaytan, Brenda L.; Duivenvoorden, Raphaël; Sager, Hendrik B.; Astudillo, Yaritzy M.; Leong, Wei; Ramachandran, Sarayu; Storm, Gert; Pérez-Medina, Carlos; Reiner, Thomas; Cormode, David P.; Strijkers, Gustav J.; Stroes, Erik S. G.; Swirski, Filip K.; Nahrendorf, Matthias; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J. M.

    2015-01-01

    Inflammation drives atherosclerotic plaque progression and rupture, and is a compelling therapeutic target. Consequently, attenuating inflammation by reducing local macrophage accumulation is an appealing approach. This can potentially be accomplished by either blocking blood monocyte recruitment to the plaque or increasing macrophage apoptosis and emigration. Because macrophage proliferation was recently shown to dominate macrophage accumulation in advanced plaques, locally inhibiting macrophage proliferation may reduce plaque inflammation and produce long-term therapeutic benefits. To test this hypothesis, we used nanoparticle-based delivery of simvastatin to inhibit plaque macrophage proliferation in apolipoprotein E–deficient mice (Apoe−/−) with advanced atherosclerotic plaques. This resulted in the rapid reduction of plaque inflammation and favorable phenotype remodeling. We then combined this short-term nanoparticle intervention with an 8-week oral statin treatment, and this regimen rapidly reduced and continuously suppressed plaque inflammation. Our results demonstrate that pharmacologically inhibiting local macrophage proliferation can effectively treat inflammation in atherosclerosis. PMID:26295063

  1. Cryptococcus neoformans Variants Generated by Phenotypic Switching Differ in Virulence through Effects on Macrophage Activation▿ †

    PubMed Central

    Guerrero, A.; Jain, N.; Wang, X.; Fries, B. C.

    2010-01-01

    Macrophages have a central role in the pathogenesis of cryptococcosis since they are an important line of defense, serve as a site for fungal replication, and also can contribute to tissue damage. The objective of this study was to investigate the interaction of macrophages with cells from smooth-colony variants (SM) and mucoid-colony variants (MC) arising from phenotypic switching of Cryptococcus neoformans. Alveolar macrophages (AMs) isolated from SM- and MC-infected mice exhibited differences in gene and surface expression of PD-L1, PD-L2, and major histocompatibility class II (MHC-II). PD-L1 and PD-L2 are the ligands for PD1 and are differentially regulated in Th1- and Th2-type cells. In addition, macrophage activation in SM- and MC-infected mice was characterized as alternatively activated. Flow cytometric and cytokine analysis demonstrated that MC infection was associated with the emergence of Th17 cells and higher levels of interleukin-17 (IL-17) in lung tissue, which were reduced by AM depletion. In conclusion, our results indicate that macrophages play a significant role in maintaining damage-promoting inflammation in the lung during MC infection, which ultimately results in death. PMID:20048044

  2. TLR-mediated secretion of endoplasmic reticulum aminopeptidase 1 from macrophages.

    PubMed

    Goto, Yoshikuni; Ogawa, Kenji; Nakamura, Takahiro J; Hattori, Akira; Tsujimoto, Masafumi

    2014-05-01

    Macrophages play an important role in host defense under several immunological, inflammatory, and/or infectious conditions. In our previous work, we demonstrated that endoplasmic reticulum aminopeptidase 1 (ERAP1) was secreted from macrophages in response to LPS and IFN-γ, and it enhanced their phagocytic activity. In this study, we analyzed the mechanism of LPS/IFN-γ-induced ERAP1 secretion. LPS/IFN-γ-induced secretion of the enzyme from the murine macrophage cell line RAW264.7 was suppressed by polymyxin B. Several agonists of TLRs, such as Pam3CSK4, FSL-1, and ODN1826, induced its secretion. In contrast, neutralizing Abs to IFN-β and TNF-α receptor type 1 suppressed its secretion. Using murine peritoneal macrophages derived from TNF-α and type 1 IFNR knockout mice, we confirmed the involvement of these two cytokines in ERAP1 secretion. In addition, secretion of ERAP1 from both RAW264.7 cells and murine peritoneal macrophages was induced by A23187 and thapsigargin and inhibited by BAPTA-AM and the calmodulin inhibitor W7. These results suggest that LPS/IFN-γ-induced secretion of ERAP1 is mediated by TLRs via induction of intermediate cytokines such as IFN-β and TNF-α, which in turn lead to enhanced cytosolic Ca(2+) levels and calmodulin activation. PMID:24688025

  3. Candida albicans Hypha Formation and Mannan Masking of β-Glucan Inhibit Macrophage Phagosome Maturation

    PubMed Central

    Louw, Johanna; Lewis, Leanne E.; Okai, Blessing; Walls, Catriona A.; Ballou, Elizabeth R.; Walker, Louise A.; Reid, Delyth; Munro, Carol A.; Brown, Alistair J. P.; Brown, Gordon D.; Gow, Neil A. R.; Erwig, Lars P.

    2014-01-01

    ABSTRACT Candida albicans is a major life-threatening human fungal pathogen in the immunocompromised host. Host defense against systemic Candida infection relies heavily on the capacity of professional phagocytes of the innate immune system to ingest and destroy fungal cells. A number of pathogens, including C. albicans, have evolved mechanisms that attenuate the efficiency of phagosome-mediated inactivation, promoting their survival and replication within the host. Here we visualize host-pathogen interactions using live-cell imaging and show that viable, but not heat- or UV-killed C. albicans cells profoundly delay phagosome maturation in macrophage cell lines and primary macrophages. The ability of C. albicans to delay phagosome maturation is dependent on cell wall composition and fungal morphology. Loss of cell wall O-mannan is associated with enhanced acquisition of phagosome maturation markers, distinct changes in Rab GTPase acquisition by the maturing phagosome, impaired hyphal growth within macrophage phagosomes, profound changes in macrophage actin dynamics, and ultimately a reduced ability of fungal cells to escape from macrophage phagosomes. The loss of cell wall O-mannan leads to exposure of β-glucan in the inner cell wall, facilitating recognition by Dectin-1, which is associated with enhanced phagosome maturation. PMID:25467440

  4. Aberrant host defense against Leishmania major in the absence of SLPI

    PubMed Central

    McCartney-Francis, Nancy; Jin, Wenwen; Belkaid, Yasmine; McGrady, George; Wahl, Sharon M.

    2014-01-01

    SLPI, a potent epithelial and myeloid-derived serine protease inhibitor with antimicrobial and anti-inflammatory functions, is induced by the intracellular parasite Leishmania major, and increased SLPI expression is evident within lesions that follow L. major infection. In contrast to self-resolving infection in C57Bl/6 WT mice, Slpi−/− mice launch a strong Th1 response to L. major, yet fail to control infection and develop destructive, nonhealing lesions with systemic spread of parasites. Because SLPI is both produced by murine macrophages and antagonizes their function, we examined the contribution of macrophage polarization to the defective host response in the absence of SLPI. Slpi−/− and Slpi+/+ macrophages were first primed with either IFNγ or IL-4 to generate classically activated M1 or alternatively activated M2 macrophages. After infection with L. major, Slpi−/− M1 macrophages expressed elevated iNOS RNA, whereas arginase was more highly expressed in WT than Slpi−/− M2 macrophages. After in vivo infection, we found that both IFNγ and iNOS were persistently overexpressed in chronic lesions in Slpi−/− mice, but surprisingly, IL-4 and arginase concomitantly remained elevated. Moreover, overexpression of the negative regulators SOCS1 and IL-27 provided insight into the failure of IFNγ to clear L. major from the dermal lesions. Notably, adenoviral delivery of SLPI to L. major-infected Slpi−/− mice significantly limited the progression of infection. These studies suggest that convergence of M1 and M2 macrophage responses may influence the outcome of innate host defense against intracellular parasites and that SLPI is critical for coordinating resistance to chronic leishmaniasis. PMID:25030421

  5. Mnn10 Maintains Pathogenicity in Candida albicans by Extending α-1,6-Mannose Backbone to Evade Host Dectin-1 Mediated Antifungal Immunity.

    PubMed

    Zhang, Shi Qun; Zou, Zui; Shen, Hui; Shen, Shuai Shuai; Miao, Qi; Huang, Xin; Liu, Wei; Li, Li Ping; Chen, Si Min; Yan, Lan; Zhang, Jun Dong; Zhao, Jing Jun; Xu, Guo Tong; An, Mao Mao; Jiang, Yuan Ying

    2016-05-01

    The cell wall is a dynamic structure that is important for the pathogenicity of Candida albicans. Mannan, which is located in the outermost layer of the cell wall, has been shown to contribute to the pathogenesis of C. albicans, however, the molecular mechanism by which this occurs remains unclear. Here we identified a novel α-1,6-mannosyltransferase encoded by MNN10 in C. albicans. We found that Mnn10 is required for cell wall α-1,6-mannose backbone biosynthesis and polysaccharides organization. Deletion of MNN10 resulted in significant attenuation of the pathogenesis of C. albicans in a murine systemic candidiasis model. Inhibition of α-1,6-mannose backbone extension did not, however, impact the invasive ability of C. albicans in vitro. Notably, mnn10 mutant restored the invasive capacity in athymic nude mice, which further supports the notion of an enhanced host antifungal defense related to this backbone change. Mnn10 mutant induced enhanced Th1 and Th17 cell mediated antifungal immunity, and resulted in enhanced recruitment of neutrophils and monocytes for pathogen clearance in vivo. We also demonstrated that MNN10 could unmask the surface β-(1,3)-glucan, a crucial pathogen-associated molecular pattern (PAMP) of C. albicans recognized by host Dectin-1. Our results demonstrate that mnn10 mutant could stimulate an enhanced Dectin-1 dependent immune response of macrophages in vitro, including the activation of nuclear factor-κB, mitogen-activated protein kinase pathways, and secretion of specific cytokines such as TNF-α, IL-6, IL-1β and IL-12p40. In summary, our study indicated that α-1,6-mannose backbone is critical for the pathogenesis of C. albicans via shielding β-glucan from recognition by host Dectin-1 mediated immune recognition. Moreover, our work suggests that inhibition of α-1,6-mannose extension by Mnn10 may represent a novel modality to reduce the pathogenicity of C. albicans. PMID:27144456

  6. Mnn10 Maintains Pathogenicity in Candida albicans by Extending α-1,6-Mannose Backbone to Evade Host Dectin-1 Mediated Antifungal Immunity

    PubMed Central

    Zhang, Shi Qun; Zou, Zui; Shen, Hui; Shen, Shuai Shuai; Miao, Qi; Huang, Xin; Liu, Wei; Li, Li Ping; Chen, Si Min; Yan, Lan; Zhang, Jun Dong; Zhao, Jing Jun; Xu, Guo Tong; An, Mao Mao; Jiang, Yuan Ying

    2016-01-01

    The cell wall is a dynamic structure that is important for the pathogenicity of Candida albicans. Mannan, which is located in the outermost layer of the cell wall, has been shown to contribute to the pathogenesis of C. albicans, however, the molecular mechanism by which this occurs remains unclear. Here we identified a novel α-1,6-mannosyltransferase encoded by MNN10 in C. albicans. We found that Mnn10 is required for cell wall α-1,6-mannose backbone biosynthesis and polysaccharides organization. Deletion of MNN10 resulted in significant attenuation of the pathogenesis of C. albicans in a murine systemic candidiasis model. Inhibition of α-1,6-mannose backbone extension did not, however, impact the invasive ability of C. albicans in vitro. Notably, mnn10 mutant restored the invasive capacity in athymic nude mice, which further supports the notion of an enhanced host antifungal defense related to this backbone change. Mnn10 mutant induced enhanced Th1 and Th17 cell mediated antifungal immunity, and resulted in enhanced recruitment of neutrophils and monocytes for pathogen clearance in vivo. We also demonstrated that MNN10 could unmask the surface β-(1,3)-glucan, a crucial pathogen-associated molecular pattern (PAMP) of C. albicans recognized by host Dectin-1. Our results demonstrate that mnn10 mutant could stimulate an enhanced Dectin-1 dependent immune response of macrophages in vitro, including the activation of nuclear factor-κB, mitogen-activated protein kinase pathways, and secretion of specific cytokines such as TNF-α, IL-6, IL-1β and IL-12p40. In summary, our study indicated that α-1,6-mannose backbone is critical for the pathogenesis of C. albicans via shielding β-glucan from recognition by host Dectin-1 mediated immune recognition. Moreover, our work suggests that inhibition of α-1,6-mannose extension by Mnn10 may represent a novel modality to reduce the pathogenicity of C. albicans. PMID:27144456

  7. Heme Oxygenase-1 Dysregulates Macrophage Polarization and the Immune Response to Helicobacter pylori

    PubMed Central

    Gobert, Alain P.; Verriere, Thomas; Asim, Mohammad; Barry, Daniel P.; Piazuelo, M. Blanca; de Sablet, Thibaut; Delgado, Alberto G.; Bravo, Luis E.; Correa, Pelayo; Peek, Richard M.; Chaturvedi, Rupesh; Wilson, Keith T.

    2014-01-01

    Helicobacter pylori incites a futile inflammatory response, which is the key feature of its immunopathogenesis. This leads to the ability of this bacterial pathogen to survive in the stomach and cause peptic ulcers and gastric cancer. Myeloid cells recruited to the gastric mucosa during Helicobacter pylori infection have been directly implicated in the modulation of host defense against the bacterium and gastric inflammation. Heme oxygenase-1 (HO-1) is an inducible enzyme that exhibits anti-inflammatory functions. Our aim was to analyze the induction and role of HO-1 in macrophages during H. pylori infection. We now show that phosphorylation of the H. pylori virulence factor cytotoxin associated gene A (CagA) in macrophages results in expression of hmox-1, the gene encoding HO-1, through p38/nuclear factor (erythroid-derived 2)-like 2 signaling. Blocking phagocytosis prevented CagA phosphorylation and HO-1 induction. The expression of HO-1 was also increased in gastric mononuclear cells of human patients and macrophages of mice infected with cagA+ H. pylori strains. Genetic ablation of hmox-1 in H. pylori-infected mice increased histologic gastritis, which was associated with enhanced M1/Th1/Th17 responses, decreased Mreg response, and reduced H. pylori colonization. Gastric macrophages of H. pylori-infected mice and macrophages infected in vitro with this bacterium showed an M1/Mreg mixed polarization type; deletion of hmox-1 or inhibition of HO-1 in macrophages caused an increased M1 and a decreased of Mreg phenotype. These data highlight a mechanism by which H. pylori impairs the immune response and favors its own survival via activation of macrophage HO-1. PMID:25108023

  8. Adverse effects of wood smoke PM2.5 exposure on macrophage functions

    PubMed Central

    Migliaccio, Christopher T.; Kobos, Emily; King, Quinton O.; Porter, Virginia; Jessop, Forrest; Ward, Tony

    2016-01-01

    Epidemiological studies have shown a correlation between chronic biomass smoke exposure and increased respiratory infection. Pulmonary macrophages are instrumental in both the innate and the adaptive immune responses to respiratory infection. In the present study, in vitro systems were utilized where alveolar macrophages (AM) and bone marrow-derived macrophages (BMdM) were exposed to concentrated wood smoke-derived particulate matter (WS-PM) and mice were exposed in vivo to either concentrated WS-PM or inhaled WS. In vivo studies demonstrated that WS-exposed mice inoculated with Streptococcus pneumoniae had a higher bacterial load 24 h post-exposure, and corresponding AM were found to have decreased lymphocyte activation activity. Additionally, while classic markers of inflammation (cellular infiltration, total protein, neutrophils) were not affected, there were changes in pulmonary macrophages populations, including significant decreases in macrophages expressing markers of activation in WS-exposed mice. The lymphocyte activation activity of WS-PM-exposed AM was significantly suppressed, but the phagocytic activity appeared unchanged. In an effort to determine a pathway for WS-induced suppression, RelB activation, assessed by nuclear translocation, was observed in AM exposed to either inhaled WS or instilled WS-PM. Finally, an analysis of WS-PM fractions determined the presence of 4–5 polycyclic aromatic hydrocarbons (PAHs), and preliminary work suggests a potential role for these PAHs to alter macrophage functions. These studies show a decreased ability of WS-exposed pulmonary macrophages to effectively mount a defense against infection, the effect lasts at least a week post-exposure, and appears to be mediated via RelB activation. PMID:23363038

  9. Bacterial Membrane Vesicles Mediate the Release of Mycobacterium tuberculosis Lipoglycans and Lipoproteins from Infected Macrophages.

    PubMed

    Athman, Jaffre J; Wang, Ying; McDonald, David J; Boom, W Henry; Harding, Clifford V; Wearsch, Pamela A

    2015-08-01

    Mycobacterium tuberculosis is an intracellular pathogen that infects lung macrophages and releases microbial factors that regulate host defense. M. tuberculosis lipoproteins and lipoglycans block phagosome maturation, inhibit class II MHC Ag presentation, and modulate TLR2-dependent cytokine production, but the mechanisms for their release during infection are poorly defined. Furthermore, these molecules are thought to be incorporated into host membranes and released from infected macrophages within exosomes, 40-150-nm extracellular vesicles that derive from multivesicular endosomes. However, our studies revealed that extracellular vesicles released from infected macrophages include two distinct, largely nonoverlapping populations: one containing host cell markers of exosomes (CD9, CD63) and the other containing M. tuberculosis molecules (lipoglycans, lipoproteins). These vesicle populations are similar in size but have distinct densities, as determined by separation on sucrose gradients. Release of lipoglycans and lipoproteins from infected macrophages was dependent on bacterial viability, implicating active bacterial mechanisms in their secretion. Consistent with recent reports of extracellular vesicle production by bacteria (including M. tuberculosis), we propose that bacterial membrane vesicles are secreted by M. tuberculosis within infected macrophages and subsequently are released into the extracellular environment. Furthermore, extracellular vesicles released from M. tuberculosis-infected cells activate TLR2 and induce cytokine responses by uninfected macrophages. We demonstrate that these activities derive from the bacterial membrane vesicles rather than exosomes. Our findings suggest that bacterial membrane vesicles are the primary means by which M. tuberculosis exports lipoglycans and lipoproteins to impair effector functions of infected macrophages and circulate bacterial components beyond the site of infection to regulate immune responses by uninfected

  10. Tumors Escape CD4+ T-cell-Mediated Immunosurveillance by Impairing the Ability of Infiltrating Macrophages to Indirectly Present Tumor Antigens.

    PubMed

    Tveita, Anders Aune; Schjesvold, Fredrik; Haabeth, Ole Audun; Fauskanger, Marte; Bogen, Bjarne

    2015-08-15

    Tumors cells can escape cytotoxic CD8+ T cells by preventing MHC I display of tumor antigens. It is unknown how tumors evade CD4+ T-cell responses, but because many tumor cells lack MHC II expression, novel mechanisms would be required. We have investigated this issue in a model in which MHC II(NEG) myeloma cells secrete a monoclonal Ig containing a V region L chain (VL) epitope recognized by CD4+ T cells. Infiltrating macrophages process and present the secreted tumor antigen to Th1 cells, resulting in induction of macrophage cytotoxicity and apparent rejection of the tumor. Despite long-term tumor protection in VL-specific T-cell receptor transgenic mice, we here describe that some myeloma cells persisted in a dormant state and, eventually, formed expanding tumors. Escape tumor cells maintained their secretion of complete (H+L) monoclonal Ig with unchanged sequence, while secretion of surplus free L chain was severely diminished. Although free L chains were efficiently processed and presented by tumor-infiltrating macrophages to CD4+ T cells, complete (H+L) monoclonal Ig was not. Forced overexpression of free L chain secretion reinstated tumor rejection. These results show that tumors can escape CD4+ T-cell-mediated rejection by impairing indirect presentation of tumor antigen by infiltrating macrophages. This occurs through a novel mechanism of immunoediting, in which modulation of the quaternary structure of the secreted tumor-specific antigen reduces its immunogenicity. PMID:26038231

  11. Fusion between Intestinal epithelial cells and macrophages in a cancer context results in nuclear reprogramming.

    PubMed

    Powell, Anne E; Anderson, Eric C; Davies, Paige S; Silk, Alain D; Pelz, Carl; Impey, Soren; Wong, Melissa H

    2011-02-15

    The most deadly phase in cancer progression is attributed to the inappropriate acquisition of molecular machinery leading to metastatic transformation and spread of disease to distant organs. Although it is appreciated that metastasis involves epithelial-mesenchymal interplay, the underlying mechanism defining this process is poorly understood. Specifically, how cancer cells evade immune surveillance and gain the ability to navigate the circulatory system remains a focus. One possible mechanism underlying metastatic conversion is fusion between blood-derived immune cells and cancer cells. While this notion is a century old, in vivo evidence that cell fusion occurs within tumors and imparts genetic or physiologic changes remains controversial. We have previously demonstrated in vivo cell fusion between blood cells and intestinal epithelial cells in an injury setting. Here, we hypothesize that immune cells, such as macrophages, fuse with tumor cells imparting metastatic capabilities by transferring their cellular identity. We used parabiosis to introduce fluorescent-labeled bone marrow-derived cells to mice with intestinal tumors, finding that fusion between circulating blood-derived cells and tumor epithelium occurs during the natural course of tumorigenesis. Moreover, we identify the macrophage as a key cellular partner for this process. Interestingly, cell fusion hybrids retain a transcriptome identity characteristic of both parental derivatives, while also expressing a unique subset of transcripts. Our data supports the novel possibility that tumorigenic cell fusion may impart physical behavior attributed to migratory macrophages, including navigation of circulation and immune evasion. As such, cell fusion may represent a promising novel mechanism underlying the metastatic conversion of cancer cells. PMID:21303980

  12. Pasteurella pneumotropica Evades the Human Complement System by Acquisition of the Complement Regulators Factor H and C4BP

    PubMed Central

    Sahagún-Ruiz, Alfredo; Granados Martinez, Adriana Patricia; Breda, Leandro Carvalho Dantas; Fraga, Tatiana Rodrigues; Castiblanco Valencia, Mónica Marcela; Barbosa, Angela Silva; Isaac, Lourdes

    2014-01-01

    Pasteurella pneumotropica is an opportunist Gram negative bacterium responsible for rodent pasteurellosis that affects upper respiratory, reproductive and digestive tracts of mammals. In animal care facilities the presence of P. pneumotropica causes severe to lethal infection in immunodeficient mice, being also a potential source for human contamination. Indeed, occupational exposure is one of the main causes of human infection by P. pneumotropica. The clinical presentation of the disease includes subcutaneous abscesses, respiratory tract colonization and systemic infections. Given the ability of P. pneumotropica to fully disseminate in the organism, it is quite relevant to study the role of the complement system to control the infection as well as the possible evasion mechanisms involved in bacterial survival. Here, we show for the first time that P. pneumotropica is able to survive the bactericidal activity of the human complement system. We observed that host regulatory complement C4BP and Factor H bind to the surface of P. pneumotropica, controlling the activation pathways regulating the formation and maintenance of C3-convertases. These results show that P. pneumotropica has evolved mechanisms to evade the human complement system that may increase the efficiency by which this pathogen is able to gain access to and colonize inner tissues where it may cause severe infections. PMID:25347183

  13. Escape and evade control policies for ensuring the physical security of nonholonomic, ground-based, unattended mobile sensor nodes

    NASA Astrophysics Data System (ADS)

    Mascarenas, David; Stull, Christopher; Farrar, Charles

    2011-06-01

    In order to realize the wide-scale deployment of high-endurance, unattended mobile sensing technologies, it is vital to ensure the self-preservation of the sensing assets. Deployed mobile sensor nodes face a variety of physical security threats including theft, vandalism and physical damage. Unattended mobile sensor nodes must be able to respond to these threats with control policies that facilitate escape and evasion to a low-risk state. In this work the Precision Immobilization Technique (PIT) problem has been considered. The PIT maneuver is a technique that a pursuing, car-like vehicle can use to force a fleeing vehicle to abruptly turn ninety degrees to the direction of travel. The abrupt change in direction generally causes the fleeing driver to lose control and stop. The PIT maneuver was originally developed by law enforcement to end vehicular pursuits in a manner that minimizes damage to the persons and property involved. It is easy to imagine that unattended autonomous convoys could be targets of this type of action by adversarial agents. This effort focused on developing control policies unattended mobile sensor nodes could employ to escape, evade and recover from PIT-maneuver-like attacks. The development of these control policies involved both simulation as well as small-scale experimental testing. The goal of this work is to be a step toward ensuring the physical security of unattended sensor node assets.

  14. Attenuated Rabies Virus Activates, while Pathogenic Rabies Virus Evades, the Host Innate Immune Responses in the Central Nervous System

    PubMed Central

    Wang, Zhi W.; Sarmento, Luciana; Wang, Yuhuan; Li, Xia-qing; Dhingra, Vikas; Tseggai, Tesfai; Jiang, Baoming; Fu, Zhen F.

    2005-01-01

    Rabies virus (RV) induces encephalomyelitis in humans and animals. However, the pathogenic mechanism of rabies is not fully understood. To investigate the host responses to RV infection, we examined and compared the pathology, particularly the inflammatory responses, and the gene expression profiles in the brains of mice infected with wild-type (wt) virus silver-haired bat RV (SHBRV) or laboratory-adapted virus B2C, using a mouse genomic array (Affymetrix). Extensive inflammatory responses were observed in animals infected with the attenuated RV, but little or no inflammatory responses were found in mice infected with wt RV. Furthermore, attenuated RV induced the expression of the genes involved in the innate immune and antiviral responses, especially those related to the alpha/beta interferon (IFN-α/β) signaling pathways and inflammatory chemokines. For the IFN-α/β signaling pathways, many of the interferon regulatory genes, such as the signal transduction activation transducers and interferon regulatory factors, as well as the effector genes, for example, 2′-5′-oligoadenylate synthetase and myxovirus proteins, are highly induced in mice infected with attenuated RV. However, many of these genes were not up-regulated in mice infected with wt SHBRV. The data obtained by microarray analysis were confirmed by real-time PCR. Together, these data suggest that attenuated RV activates, while pathogenic RV evades, the host innate immune and antiviral responses. PMID:16160183

  15. How much of the world’s land has been urbanized, really? A hierarchical framework for evading confusion

    SciTech Connect

    Liu, zhifeng; He, Chunyang; Zhou, Yuyu; Wu, jianguo

    2014-05-01

    Urbanization has transformed the world’s landscapes, resulting in a series of ecological and environmental problems. To assess urbanization impacts and improve sustainability, one of the first questions that we must address is: how much of the world’s land has been urbanized? Unfortunately, the estimates of the global urban land reported in the literature vary widely from less than 1% to 3% primarily because different definitions of urban land were used. To evade confusion, here we propose a hierarchical framework for representing and communicating the spatial extent of the world’s urbanized land at the global, regional, and more local levels. The hierarchical framework consists of three spatially nested definitions: “urban area” that is delineated by administrative boundaries, “built-up area” that is dominated by artificial surfaces, and “impervious surface area” that is devoid of life. These are really three different measures of urbanization. In 2010, the global urban land was close to 3%, the global built-up area was 0.65%, and the global impervious surface area was 0.45%, of the word’s total land area (excluding Antarctica and Greenland). We argue that this hierarchy of urban land measures, in particular the ratios between them, can also facilitate better understanding the biophysical and socioeconomic processes and impacts of urbanization.

  16. The West Nile virus assembly process evades the conserved antiviral mechanism of the interferon-induced MxA protein

    SciTech Connect

    Hoenen, Antje; Gillespie, Leah; Morgan, Garry; Heide, Peter van der; Khromykh, Alexander; Mackenzie, Jason

    2014-01-05

    Flaviviruses have evolved means to evade host innate immune responses. Recent evidence suggests this is due to prevention of interferon production and signaling in flavivirus-infected cells. Here we show that the interferon-induced MxA protein can sequester the West Nile virus strain Kunjin virus (WNV{sub KUN}) capsid protein in cytoplasmic tubular structures in an expression-replication system. This sequestering resulted in reduced titers of secreted WNV{sub KUN} particles. We show by electron microscopy, tomography and 3D modeling that these cytoplasmic tubular structures form organized bundles. Additionally we show that recombinant ER-targeted MxA can restrict production of infectious WNV{sub KUN} under conditions of virus infection. Our results indicate a co-ordinated and compartmentalized WNV{sub KUN} assembly process may prevent recognition of viral components by MxA, particularly the capsid protein. This recognition can be exploited if MxA is targeted to intracellular sites of WNV{sub KUN} assembly. This results in further understanding of the mechanisms of flavivirus evasion from the immune system. - Highlights: • We show that the ISG MxA can recognize the West Nile virus capsid protein. • Interaction between WNV C protein and MxA induces cytoplasmic fibrils. • MxA can be retargeted to the ER to restrict WNV particle release. • WNV assembly process is a strategy to avoid MxA recognition.

  17. Streptolysin O and NAD-Glycohydrolase Prevent Phagolysosome Acidification and Promote Group A Streptococcus Survival in Macrophages

    PubMed Central

    Bastiat-Sempe, Benedicte; Love, John F.; Lomayesva, Natalie

    2014-01-01

    ABSTRACT Group A Streptococcus (GAS, Streptococcus pyogenes) is an ongoing threat to human health as the agent of streptococcal pharyngitis, skin and soft tissue infections, and life-threatening conditions such as necrotizing fasciitis and streptococcal toxic shock syndrome. In animal models of infection, macrophages have been shown to contribute to host defense against GAS infection. However, as GAS can resist killing by macrophages in vitro and induce macrophage cell death, it has been suggested that GAS intracellular survival in macrophages may enable persistent infection. Using isogenic mutants, we now show that the GAS pore-forming toxin streptolysin O (SLO) and its cotoxin NAD-glycohydrolase (NADase) mediate GAS intracellular survival and cytotoxicity for macrophages. Unexpectedly, the two toxins did not inhibit fusion of GAS-containing phagosomes with lysosomes but rather prevented phagolysosome acidification. SLO served two essential functions, poration of the phagolysosomal membrane and translocation of NADase into the macrophage cytosol, both of which were necessary for maximal GAS intracellular survival. Whereas NADase delivery to epithelial cells is mediated by SLO secreted from GAS bound to the cell surface, in macrophages, the source of SLO and NADase is GAS contained within phagolysosomes. We found that transfer of NADase from the phagolysosome to the macrophage cytosol occurs not by simple diffusion through SLO pores but rather by a specific translocation mechanism that requires the N-terminal translocation domain of NADase. These results illuminate the mechanisms through which SLO and NADase enable GAS to defeat macrophage-mediated killing and provide new insight into the virulence of a major human pathogen. PMID:25227466

  18. Macrophages: Their Emerging Roles in Bone.

    PubMed

    Sinder, Benjamin P; Pettit, Allison R; McCauley, Laurie K

    2015-12-01

    Macrophages are present in nearly all tissues and are critical for development, homeostasis, and regeneration. Resident tissue macrophages of bone, termed osteal macrophages, are recently classified myeloid cells that are distinct from osteoclasts. Osteal macrophages are located immediately adjacent to osteoblasts, regulate bone formation, and play diverse roles in skeletal homeostasis. Genetic or pharmacological modulation of macrophages in vivo results in significant bone phenotypes, and these phenotypes depend on which macrophage subsets are altered. Macrophages are also key mediators of osseous wound healing and fracture repair, with distinct roles at various stages of the repair process. A central function of macrophages is their phagocytic ability. Each day, billions of cells die in the body and efferocytosis (phagocytosis of apoptotic cells) is a critical process in both clearing dead cells and recruitment of replacement progenitor cells to maintain homeostasis. Recent data suggest a role for efferocytosis in bone biology and these new mechanisms are outlined. Finally, although macrophages have an established role in primary tumors, emerging evidence suggests that macrophages in bone support cancers which preferentially metastasize to the skeleton. Collectively, this developing area of osteoimmunology raises new questions and promises to provide novel insights into pathophysiologic conditions as well as therapeutic and regenerative approaches vital for skeletal health. PMID:26531055

  19. Macrophages and Alcohol-Related Liver Inflammation

    PubMed Central

    Ju, Cynthia; Mandrekar, Pranoti

    2015-01-01

    Recent studies have suggested that macrophages have a critical role in the development of alcohol-induced inflammation in the liver. To define the precise pathogenic function of these cells during alcoholic liver disease (ALD), it is extremely important to conduct extensive studies in clinical settings that further elucidate the phenotypic diversity of macrophages in the context of ALD. Research to date already has identified several characteristics of macrophages that underlie the cells’ actions, including macrophage polarization and their phenotypic diversity. Other analyses have focused on the contributions of resident versus infiltrating macrophages/monocytes, as well as on the roles of macrophage mediators, in the development of ALD. Findings point to the potential of macrophages as a therapeutic target in alcoholic liver injury. Future studies directed toward understanding how alcohol affects macrophage phenotypic switch in the liver and other tissues, whether the liver microenvironment determines macrophage function in ALD, and if targeting of macrophages alleviates alcoholic liver injury, will provide promising strategies to manage patients with alcoholic hepatitis. PMID:26717583

  20. Dietary antioxidants: immunity and host defense.

    PubMed

    Puertollano, María A; Puertollano, Elena; de Cienfuegos, Gerardo Álvarez; de Pablo, Manuel A

    2011-01-01

    Natural antioxidants may be defined as molecules that prevent cell damage against free radicals and are critical for maintaining optimum health in both animals and humans. In all living systems, cells require adequate levels of antioxidant defenses in order to avoid the harmful effect of an excessive production of reactive oxygen species (ROS) and to prevent damage to the immune cells. During the inflammatory processes, the activation of phagocytes and/or the action of bacterial products with specific receptors are capable of promoting the assembly of the multicomponent flavoprotein NADPH oxidase, which catalyzes the production of high amounts of the superoxide anion radical (O(2)(-)). Under these particular circumstances, neutrophils and macrophages are recognized to produce superoxide free radicals and H(2)O(2), which are essential for defence against phagocytized or invading microbes. In this state, antioxidants are absolutely necessary to regulate the reactions that release free radicals. Antioxidant nutrients commonly included in the diet such as vitamin E, vitamin C, β-carotene, selenium, copper, iron and zinc improve different immune function exhibiting an important protective role in infections caused by bacteria, viruses or parasites. As a result, dietary antioxidants have been related to modulate the host susceptibility or resistance to infectious pathogens. Overall, numerous studies have suggested that the development of tolerance, and control of inflammation are strongly correlated with specific immune mechanisms that may be altered by an inadequate supply of either macronutrients or micronutrients. Therefore, the present paper will review the effects of dietary antioxidants on immune cell function and the impact on protection against infectious microorganisms. PMID:21506934

  1. Activation of Hepatic STAT3 Maintains Pulmonary Defense during Endotoxemia

    PubMed Central

    Hilliard, Kristie L.; Allen, Eri; Traber, Katrina E.; Kim, Yuri; Wasserman, Gregory A.; Jones, Matthew R.; Mizgerd, Joseph P.

    2015-01-01

    Pneumonia and infection-induced sepsis are worldwide public health concerns. Both pathologies elicit systemic inflammation and induce a robust acute-phase response (APR). Although APR activation is well regarded as a hallmark of infection, the direct contributions of liver activation to pulmonary defense during sepsis remain unclear. By targeting STAT3-dependent acute-phase changes in the liver, we evaluated the role of liver STAT3 activity in promoting host defense in the context of sepsis and pneumonia. We employed a two-hit endotoxemia/pneumonia model, whereby administration of 18 h of intraperitoneal lipopolysaccharide (LPS; 5 mg/kg of body weight) was followed by intratracheal Escherichia coli (106 CFU) in wild-type mice or those lacking hepatocyte STAT3 (hepSTAT3−/−). Pneumonia alone (without endotoxemia) was effectively controlled in the absence of liver STAT3. Following endotoxemia and pneumonia, however, hepSTAT3−/− mice, with significantly reduced levels of circulating and airspace acute-phase proteins, exhibited significantly elevated lung and blood bacterial burdens and mortality. These data suggested that STAT3-dependent liver responses are necessary to promote host defense. While neither recruited airspace neutrophils nor lung injury was altered in endotoxemic hepSTAT3−/− mice, alveolar macrophage reactive oxygen species generation was significantly decreased. Additionally, bronchoalveolar lavage fluid from this group of hepSTAT3−/− mice allowed greater bacterial growth ex vivo. These results suggest that hepatic STAT3 activation promotes both cellular and humoral lung defenses. Taken together, induction of liver STAT3-dependent gene expression programs is essential to countering the deleterious consequences of sepsis on pneumonia susceptibility. PMID:26216424

  2. Activation of Hepatic STAT3 Maintains Pulmonary Defense during Endotoxemia.

    PubMed

    Hilliard, Kristie L; Allen, Eri; Traber, Katrina E; Kim, Yuri; Wasserman, Gregory A; Jones, Matthew R; Mizgerd, Joseph P; Quinton, Lee J

    2015-10-01

    Pneumonia and infection-induced sepsis are worldwide public health concerns. Both pathologies elicit systemic inflammation and induce a robust acute-phase response (APR). Although APR activation is well regarded as a hallmark of infection, the direct contributions of liver activation to pulmonary defense during sepsis remain unclear. By targeting STAT3-dependent acute-phase changes in the liver, we evaluated the role of liver STAT3 activity in promoting host defense in the context of sepsis and pneumonia. We employed a two-hit endotoxemia/pneumonia model, whereby administration of 18 h of intraperitoneal lipopolysaccharide (LPS; 5 mg/kg of body weight) was followed by intratracheal Escherichia coli (10(6) CFU) in wild-type mice or those lacking hepatocyte STAT3 (hepSTAT3(-/-)). Pneumonia alone (without endotoxemia) was effectively controlled in the absence of liver STAT3. Following endotoxemia and pneumonia, however, hepSTAT3(-/-) mice, with significantly reduced levels of circulating and airspace acute-phase proteins, exhibited significantly elevated lung and blood bacterial burdens and mortality. These data suggested that STAT3-dependent liver responses are necessary to promote host defense. While neither recruited airspace neutrophils nor lung injury was altered in endotoxemic hepSTAT3(-/-) mice, alveolar macrophage reactive oxygen species generation was significantly decreased. Additionally, bronchoalveolar lavage fluid from this group of hepSTAT3(-/-) mice allowed greater bacterial growth ex vivo. These results suggest that hepatic STAT3 activation promotes both cellular and humoral lung defenses. Taken together, induction of liver STAT3-dependent gene expression programs is essential to countering the deleterious consequences of sepsis on pneumonia susceptibility. PMID:26216424

  3. Storage xyloglucans: potent macrophages activators.

    PubMed

    do Rosário, Marianna Maia Taulois; Kangussu-Marcolino, Mônica Mendes; do Amaral, Alex Evangelista; Noleto, Guilhermina Rodrigues; Petkowicz, Carmen Lúcia de Oliveira

    2011-01-15

    Storage xyloglucans from the seeds of Copaifera langsdorffii, Hymenaea courbaril and Tamarindus indica were obtained by aqueous extraction from the milled and defatted cotyledons, XGC, XGJ and XGT, respectively. The resulting fractions showed similar monosaccharide composition with Glc:Xyl:Gal molar ratios of 2.4:1.5:1.0, 3.8:1.5:1,0 and 3.6:2.4:1.0 for XGC, XGJ and XGT, respectively. High-performance size-exclusion chromatography of the polysaccharides showed unimodal profiles, and the average molar mass (M(w)) was obtained for XGC (9.6 × 10⁵ g/mol), XGJ (9.1 × 10⁵ g/mol) and XGT (7.3 × 10⁵ g/mol). The immunomodulatory effects of the xyloglucans on peritoneal macrophages were evaluated. Phagocytic activity was observed in macrophages treated with XGT. The effect of XGT was tested on the production of O₂(.-) and NO. At 25 μg/ml XGT caused a 100% increase in NO production when compared to the control group; however, it did not affect O₂(.-) production in the absence of PMA. The production of TNF-α, interleukins 1β and 6 by macrophages in the presence of the xyloglucans was evaluated. The polysaccharides affected the production of the cytokines by macrophages to different degrees. XGC caused an enhancement of IL-1β and TNF-α production, compared to the other xyloglucans. For IL-6 production, XGT gave greater stimulation than XGC and XGJ, reaching 87% at 50 μg/ml. XGJ promoted a statistically significant effect on all cytokine productions tested. The results indicate that the xyloglucans from C. langsdorffii, H. courbaril and T. indica can be classified as biological response modifiers (BRM). PMID:20888807

  4. Macrophages in resistance to candidiasis.

    PubMed Central

    Vázquez-Torres, A; Balish, E

    1997-01-01

    Candida albicans, an increasingly common opportunistic pathogenic fungus, frequently causes disease in immunodeficient but not immunocompetent hosts. Clarifying the role of the phagocytic cells that participate in resistance to candidiasis not only is basic to understanding how the host copes with this dimorphic pathogen but also will expedite the development of innovative prophylactic and therapeutic approaches for treating the multiple clinical presentations that candidiasis encompasses. In this review, we present evidence that a diverse population of mononuclear phagocytes, in different states of activation and differentiation and from a variety of host species, can phagocytize C. albicans blastoconidia via an array of opsonic and nonopsonic mechanisms and can kill C. albicans blastoconidia and hyphae by means of oxygen-dependent and -independent mechanisms. Reactive nitrogen intermediates should now be added to the well-established candidacidal reactive oxygen intermediates of macrophages. Furthermore, what were thought to be two independent pathways, i.e., nitric oxide and superoxide anion, have now been shown to combine to form a potent macrophage candidacidal molecule, peroxynitrite. In contrast to monocytes and neutrophils, which are important in resistance to early stages of C. albicans infections, more differentiated macrophages activated by cytokines such as gamma interferon participate in the acquired resistance of hosts with C. albicans-specific, cell-mediated immunity. Evidence presented in this review demonstrates that mononuclear phagocytes, in some instances in the absence of other professional phagocytes such as neutrophils, play an import role in resistance to systemic and mucosal candidiasis. PMID:9184009

  5. [Case of Rh (-) patient's right lobectomy of the liver with massive hemorrhage evading allogeneic blood transfusion by hemodilutional autologous blood transfusion].

    PubMed

    Nishimura, Masayuki; Takada, Norikazu; Hashiba, Eiji; Kimura, Futoshi; Kitayama, Masatou; Hashimoto, Hiroshi

    2014-01-01

    A 44-year-old man (ASA-PS 1) underwent right lobectomy of the liver under total intravenous anesthesia with propofol, remifentanil, ketamine and rocuronium. In order to evade allogeneic blood transfusion, 1,200 g of the patient's blood was taken and hemodilution was induced for autologous blood transfusion (HAT) after the induction of anesthesia. As intraoperative blood loss amounted to about 4,000 g, Hb level decreased from 13.6 to 6.2 g x dl(-1). However, as intraoperative hemodynamics was relatively stable with crystalloidal and colloidal transfusion with no ischemic change on ECG and no metabolic acidosis, autologous blood transfusion was withheld. After returning the autologous blood, Hb increased to 9.8 g x dl(-1). Any postoperative complications related to the low Hb level were not recognized. HAT is a useful method to evade or at least decrease the amount of allogeneic blood transfusion by anesthesiologists. PMID:24558939

  6. Midbrain circuits for defensive behaviour.

    PubMed

    Tovote, Philip; Esposito, Maria Soledad; Botta, Paolo; Chaudun, Fabrice; Fadok, Jonathan P; Markovic, Milica; Wolff, Steffen B E; Ramakrishnan, Charu; Fenno, Lief; Deisseroth, Karl; Herry, Cyril; Arber, Silvia; Lüthi, Andreas

    2016-06-01

    Survival in threatening situations depends on the selection and rapid execution of an appropriate active or passive defensive response, yet the underlying brain circuitry is not understood. Here we use circuit-based optogenetic, in vivo and in vitro electrophysiological, and neuroanatomical tracing methods to define midbrain periaqueductal grey circuits for specific defensive behaviours. We identify an inhibitory pathway from the central nucleus of the amygdala to the ventrolateral periaqueductal grey that produces freezing by disinhibition of ventrolateral periaqueductal grey excitatory outputs to pre-motor targets in the magnocellular nucleus of the medulla. In addition, we provide evidence for anatomical and functional interaction of this freezing pathway with long-range and local circuits mediating flight. Our data define the neuronal circuitry underlying the execution of freezing, an evolutionarily conserved defensive behaviour, which is expressed by many species including fish, rodents and primates. In humans, dysregulation of this 'survival circuit' has been implicated in anxiety-related disorders. PMID:27279213

  7. Inducible defenses, phenotypic variability and biotic environments.

    PubMed

    Adler, F R; Drew Harvell, C

    1990-12-01

    Defensive morphologies, chemicals and behaviors induced by cues from consumers or competitors have been described in numerous organisms. Much work has focused on the costs of defenses and the actual cues used. Here, we review recent progress in determining the effects of inducible defenses on consumers and the cues implicated in inducing defenses against consumers and competitors, thereby laying the groundwork for studying the implications of inducible defenses for the dynamics of foraging, population size and evolution. PMID:21232402

  8. Epithelial antimicrobial peptides in host defense against infection

    PubMed Central

    Bals, Robert

    2000-01-01

    One component of host defense at mucosal surfaces seems to be epithelium-derived antimicrobial peptides. Antimicrobial peptides are classified on the basis of their structure and amino acid motifs. Peptides of the defensin, cathelicidin, and histatin classes are found in humans. In the airways, α-defensins and the cathelicidin LL-37/hCAP-18 originate from neutrophils. β-Defensins and LL-37/hCAP-18 are produced by the respiratory epithelium and the alveolar macrophage and secreted into the airway surface fluid. Beside their direct antimicrobial function, antimicrobial peptides have multiple roles as mediators of inflammation with effects on epithelial and inflammatory cells, influencing such diverse processes as proliferation, immune induction, wound healing, cytokine release, chemotaxis, protease-antiprotease balance, and redox homeostasis. Further, antimicrobial peptides qualify as prototypes of innovative drugs that might be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation. PMID:11667978

  9. Bulgy tadpoles: inducible defense morph.

    PubMed

    Kishida, Osamu; Nishimura, Kinya

    2004-08-01

    Predator induced morphological defenses are marked morphological shifts induced directly by cues associated with a predator. Generally, remote cues, i.e., chemical substances emitted from predators or injured conspecifics, are considered to be ideal signals to induce morphological change in aquatic environments rather than close cues, i.e., close chemical or tactile cues, since chemical substances that can propagate over relatively long distances and persist for a long period may allow organisms to keep safe and to deliberately change their morph. In fact, most organisms adopting an inducible morphological defense utilize remote chemical cues to detect predation risk and to produce morphological defenses. In this paper, we report a unique and functionally well designed inducible morphological defense strategy where the induction process requires close cues from a predator. The tadpoles of Rana pirica exhibited a bulgy bodied morphology when threatened with predation by larval salamanders, Hynobius retardatus, in close proximity. Predation trials and a function experiment showed that the induced bulgy morph is an adaptive defense phenotype against the gape-limited predator larval H. retardatus. Furthermore, R. pirica tadpoles use two adaptive strategies in terms of cost saving, i.e., adjustment of the extent of bulginess according to predation risk and reversibility by actual shrink of bulgy body after removing the predation threat. In general, R. pirica hatch earlier than H. retardatus. In natural ponds, during the early developmental stage R. pirica tadpoles live in close proximity to young H. retardatus larvae. As they grow, the salamanders gradually become serious predators and the predator-prey interaction becomes intimate. After a while, predation, cannibalism and metamorphosis decrease the number of salamanders in the ponds, and the predator-prey interaction weakens. Such a phenology in the predator-prey interaction allows the evolution of a close

  10. Induction of Macrophage Function in Human THP-1 Cells Is Associated with Rewiring of MAPK Signaling and Activation of MAP3K7 (TAK1) Protein Kinase

    PubMed Central

    Richter, Erik; Ventz, Katharina; Harms, Manuela; Mostertz, Jörg; Hochgräfe, Falko

    2016-01-01

    Macrophages represent the primary human host response to pathogen infection and link the immediate defense to the adaptive immune system. Mature tissue macrophages convert from circulating monocyte precursor cells by terminal differentiation in a process that is not fully understood. Here, we analyzed the protein kinases of the human monocytic cell line THP-1 before and after induction of macrophage differentiation by using kinomics and phosphoproteomics. When comparing the macrophage-like state with the monocytic precursor, 50% of the kinome was altered in expression and even 71% of covered kinase phosphorylation sites were affected. Kinome rearrangements are for example characterized by a shift of overrepresented cyclin-dependent kinases associated with cell cycle control in monocytes to calmodulin-dependent kinases and kinases involved in proinflammatory signaling. Eventually, we show that monocyte-to-macrophage differentiation is associated with major rewiring of mitogen-activated protein kinase signaling networks and demonstrate that protein kinase MAP3K7 (TAK1) acts as the key signaling hub in bacterial killing, chemokine production and differentiation. Our study proves the fundamental role of protein kinases and cellular signaling as major drivers of macrophage differentiation and function. The finding that MAP3K7 is central to macrophage function suggests MAP3K7 and its networking partners as promising targets in host-directed therapy for macrophage-associated disease. PMID:27066479

  11. Transnational architecting for homeland defense

    NASA Astrophysics Data System (ADS)

    O'Brien, Thomas W.

    2002-07-01

    The homeland security interests of a many nations are being increasingly threatened by the proliferation of weapons of mass destruction, drug trafficking, mass migration, global terrorism, environmental concerns, international crime and other global issues. This paper presents the case for development of such a transnational ballistic missile defense architecture for homeland defense and specifically addresses the architecture methodology and process, as well as the potential benefits and the top-level architecture trade issues that would have to be addressed if the community should decide to seriously pursue such an approach.

  12. RNase 7 in Cutaneous Defense

    PubMed Central

    Rademacher, Franziska; Simanski, Maren; Harder, Jürgen

    2016-01-01

    RNase 7 belongs to the RNase A superfamily and exhibits a broad spectrum of antimicrobial activity against various microorganisms. RNase 7 is expressed in human skin, and expression in keratinocytes can be induced by cytokines and microbes. These properties suggest that RNase 7 participates in innate cutaneous defense. In this review, we provide an overview about the role of RNase 7 in cutaneous defense with focus on the molecular mechanism of the antimicrobial activity of RNase 7, the regulation of RNase 7 expression, and the role of RNase 7 in skin diseases. PMID:27089327

  13. 76 FR 53119 - Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-25

    ... of Availability (NOA) in the Federal Register (76 FR 28757) announcing the revised Defense Logistics... Office of the Secretary Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense Logistics Agency Actions AGENCY: Defense Logistics Agency, Department of Defense....

  14. 22 CFR 120.44 - Foreign defense article or defense service.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Foreign defense article or defense service. 120.44 Section 120.44 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.44 Foreign defense article or defense service. Foreign defense article...

  15. Identification of BCAP-{sub L} as a negative regulator of the TLR signaling-induced production of IL-6 and IL-10 in macrophages by tyrosine phosphoproteomics

    SciTech Connect

    Matsumura, Takayuki; Oyama, Masaaki; Kozuka-Hata, Hiroko; Ishikawa, Kosuke; Inoue, Takafumi; Muta, Tatsushi; Semba, Kentaro; Inoue, Jun-ichiro

    2010-09-17

    Research highlights: {yields} Twenty five tyrosine-phosphorylated proteins in LPS-stimulated macrophages were determined. {yields} BCAP is a novel tyrosine-phosphorylated protein in LPS-stimulated macrophages. {yields} BCAP-{sub L} inhibits IL-6 and IL-10 production in LPS-stimulated macrophages. -- Abstract: Toll-like receptor (TLR) signaling in macrophages is essential for anti-pathogen responses such as cytokine production and antigen presentation. Although numerous reports suggest that protein tyrosine kinases (PTKs) are involved in cytokine induction in response to lipopolysaccharides (LPS; TLR4 ligand) in macrophages, the PTK-mediated signal transduction pathway has yet to be analyzed in detail. Here, we carried out a comprehensive and quantitative dynamic tyrosine phosphoproteomic analysis on the TLR4-mediated host defense system in RAW264.7 macrophages using stable isotope labeling by amino acids in cell culture (SILAC). We determined the temporal profiles of 25 proteins based on SILAC-encoded peptide(s). Of these, we focused on the tyrosine phosphorylation of B-cell adaptor for phosphatidylinositol 3-kinase (BCAP) because the function of BCAP remains unknown in TLR signaling in macrophages. Furthermore, Bcap has two distinct transcripts, a full-length (Bcap-{sub L}) and an alternatively initiated or spliced (Bcap-{sub S}) mRNA, and little is known about the differential functions of the BCAP-{sub L} and BCAP-{sub S} proteins. Our study showed, for the first time, that RNAi-mediated selective depletion of BCAP-{sub L} enhanced IL-6 and IL-10 production but not TNF-{alpha} production in TLR ligand-stimulated macrophages. We propose that BCAP-{sub L} (but not BCAP-{sub S}) is a negative regulator of the TLR-mediated host defense system in macrophages.

  16. LL-37 immunomodulatory activity during Mycobacterium tuberculosis infection in macrophages.

    PubMed

    Torres-Juarez, Flor; Cardenas-Vargas, Albertina; Montoya-Rosales, Alejandra; González-Curiel, Irma; Garcia-Hernandez, Mariana H; Enciso-Moreno, Jose A; Hancock, Robert E W; Rivas-Santiago, Bruno

    2015-12-01

    Tuberculosis is one of the most important infectious diseases worldwide. The susceptibility to this disease depends to a great extent on the innate immune response against mycobacteria. Host defense peptides (HDP) are one of the first barriers to counteract infection. Cathelicidin (LL-37) is an HDP that has many immunomodulatory effects besides its weak antimicrobial activity. Despite advances in the study of the innate immune response in tuberculosis, the immunological role of LL-37 during M. tuberculosis infection has not been clarified. Monocyte-derived macrophages were infected with M. tuberculosis strain H37Rv and then treated with 1, 5, or 15 μg/ml of exogenous LL-37 for 4, 8, and 24 h. Exogenous LL-37 decreased tumor necrosis factor alpha (TNF-α) and interleukin-17 (IL-17) while inducing anti-inflammatory IL-10 and transforming growth factor β (TGF-β) production. Interestingly, the decreased production of anti-inflammatory cytokines did not reduce antimycobacterial activity. These results are consistent with the concept that LL-37 can modulate the expression of cytokines during mycobacterial infection and this activity was independent of the P2X7 receptor. Thus, LL-37 modulates the response of macrophages during infection, controlling the expression of proinflammatory and anti-inflammatory cytokines. PMID:26351280

  17. LL-37 Immunomodulatory Activity during Mycobacterium tuberculosis Infection in Macrophages

    PubMed Central

    Torres-Juarez, Flor; Cardenas-Vargas, Albertina; Montoya-Rosales, Alejandra; González-Curiel, Irma; Garcia-Hernandez, Mariana H.; Enciso-Moreno, Jose A.; Hancock, Robert E. W.

    2015-01-01

    Tuberculosis is one of the most important infectious diseases worldwide. The susceptibility to this disease depends to a great extent on the innate immune response against mycobacteria. Host defense peptides (HDP) are one of the first barriers to counteract infection. Cathelicidin (LL-37) is an HDP that has many immunomodulatory effects besides its weak antimicrobial activity. Despite advances in the study of the innate immune response in tuberculosis, the immunological role of LL-37 during M. tuberculosis infection has not been clarified. Monocyte-derived macrophages were infected with M. tuberculosis strain H37Rv and then treated with 1, 5, or 15 μg/ml of exogenous LL-37 for 4, 8, and 24 h. Exogenous LL-37 decreased tumor necrosis factor alpha (TNF-α) and interleukin-17 (IL-17) while inducing anti-inflammatory IL-10 and transforming growth factor β (TGF-β) production. Interestingly, the decreased production of anti-inflammatory cytokines did not reduce antimycobacterial activity. These results are consistent with the concept that LL-37 can modulate the expression of cytokines during mycobacterial infection and this activity was independent of the P2X7 receptor. Thus, LL-37 modulates the response of macrophages during infection, controlling the expression of proinflammatory and anti-inflammatory cytokines. PMID:26351280

  18. Analytical workflow profiling gene expression in murine macrophages

    PubMed Central

    Nixon, Scott E.; González-Peña, Dianelys; Lawson, Marcus A.; McCusker, Robert H.; Hernandez, Alvaro G.; O’Connor, Jason C.; Dantzer, Robert; Kelley, Keith W.

    2015-01-01

    Comprehensive and simultaneous analysis of all genes in a biological sample is a capability of RNA-Seq technology. Analysis of the entire transcriptome benefits from summarization of genes at the functional level. As a cellular response of interest not previously explored with RNA-Seq, peritoneal macrophages from mice under two conditions (control and immunologically challenged) were analyzed for gene expression differences. Quantification of individual transcripts modeled RNA-Seq read distribution and uncertainty (using a Beta Negative Binomial distribution), then tested for differential transcript expression (False Discovery Rate-adjusted p-value < 0.05). Enrichment of functional categories utilized the list of differentially expressed genes. A total of 2079 differentially expressed transcripts representing 1884 genes were detected. Enrichment of 92 categories from Gene Ontology Biological Processes and Molecular Functions, and KEGG pathways were grouped into 6 clusters. Clusters included defense and inflammatory response (Enrichment Score = 11.24) and ribosomal activity (Enrichment Score = 17.89). Our work provides a context to the fine detail of individual gene expression differences in murine peritoneal macrophages during immunological challenge with high throughput RNA-Seq. PMID:25708305

  19. Changes in macrophage function modulated by the lipid environment.

    PubMed

    Williams, Michael R; Cauvi, David M; Rivera, Isabel; Hawisher, Dennis; De Maio, Antonio

    2016-04-01

    Macrophages (Mφs) play a critical role in the defense against pathogens, orchestrating the inflammatory response during injury and maintaining tissue homeostasis. During these processes, macrophages encounter a variety of environmental conditions that are likely to change their gene expression pattern, which modulates their function. In this study, we found that murine Mφs displayed two different subpopulations characterized by differences in morphologies, expression of surface markers and phagocytic capacity under non-stimulated conditions. These two subpopulations could be recapitulated by changes in the culture conditions. Thus, Mφs grown in suspension in the presence of serum were highly phagocytic, whereas subtraction of serum resulted in rapid attachment and reduced phagocytic activity. The difference in phagocytosis between these subpopulations was correlated with the expression levels of FcγR. These two cell subpopulations also differed in their responses to LPS and the expression of surface markers, including CD14, CD86, scavenger receptor A1, TLR4 and low-density lipoprotein receptor. Moreover, we found that the lipid/cholesterol content in the culture medium mediated the differences between these two cell subpopulations. Thus, we described a mechanism that modulates Mφ function depending on the exposure to lipids within their surrounding microenvironment. PMID:26951856

  20. Physical detection of influenza A epitopes identifies a stealth subset on human lung epithelium evading natural CD8 immunity

    PubMed Central

    Keskin, Derin B.; Reinhold, Bruce B.; Zhang, Guang Lan; Ivanov, Alexander R.; Karger, Barry L.; Reinherz, Ellis L.

    2015-01-01

    Vaccines eliciting immunity against influenza A viruses (IAVs) are currently antibody-based with hemagglutinin-directed antibody titer the only universally accepted immune correlate of protection. To investigate the disconnection between observed CD8 T-cell responses and immunity to IAV, we used a Poisson liquid chromatography data-independent acquisition MS method to physically detect PR8/34 (H1N1), X31 (H3N2), and Victoria/75 (H3N2) epitopes bound to HLA-A*02:01 on human epithelial cells following in vitro infection. Among 32 PR8 peptides (8–10mers) with predicted IC50 < 60 nM, 9 were present, whereas 23 were absent. At 18 h postinfection, epitope copies per cell varied from a low of 0.5 for M13–11 to a high of >500 for M158–66 with PA, HA, PB1, PB2, and NA epitopes also detected. However, aside from M158–66, natural CD8 memory responses against conserved presented epitopes were either absent or only weakly observed by blood Elispot. Moreover, the functional avidities of the immunodominant M158–66/HLA-A*02:01-specific T cells were so poor as to be unable to effectively recognize infected human epithelium. Analysis of T-cell responses to primary PR8 infection in HLA-A*02:01 transgenic B6 mice underscores the poor avidity of T cells recognizing M158–66. By maintaining high levels of surface expression of this epitope on epithelial and dendritic cells, the virus exploits the combination of immunodominance and functional inadequacy to evade HLA-A*02:01-restricted T-cell immunity. A rational approach to CD8 vaccines must characterize processing and presentation of pathogen-derived epitopes as well as resultant immune responses. Correspondingly, vaccines may be directed against “stealth” epitopes, overriding viral chicanery. PMID:25646416

  1. Tissue-resident macrophages: then and now.

    PubMed

    Davies, Luke C; Taylor, Philip R

    2015-04-01

    Macrophages have been at the heart of immune research for over a century and are an integral component of innate immunity. Macrophages are often viewed as terminally differentiated monocytic phagocytes. They infiltrate tissues during inflammation, and form polarized populations that perform pro-inflammatory or anti-inflammatory functions. Tissue-resident macrophages were regarded as differentiated monocytes, which seed the tissues to perform immune sentinel and homeostatic functions. However, tissue-resident macrophages are not a homogeneous population, but are in fact a grouping of cells with similar functions and phenotypes. In the last decade, it has been revealed that many of these cells are not terminally differentiated and, in most cases, are not derived from haematopoiesis in the adult. Recent research has highlighted that tissue-resident macrophages cannot be grouped into simple polarized categories, especially in vivo, when they are exposed to complex signalling events. It has now been demonstrated that the tissue environment itself is a major controller of macrophage phenotype, and can influence the expression of many genes regardless of origin. This is consistent with the concept that cells within different tissues have diverse responses in inflammation. There is still a mountain to climb in the field, as it evolves to encompass not only tissue-resident macrophage diversity, but also categorization of specific tissue environments and the plasticity of macrophages themselves. This knowledge provides a new perspective on therapeutic strategies, as macrophage subsets can potentially be manipulated to control the inflammatory environment in a tissue-specific manner. PMID:25684236

  2. Development and maintainance of resident macrophages

    PubMed Central

    Perdiguero, Elisa Gomez; Geissmann, Frederic

    2016-01-01

    The molecular and cellular mechanisms that underlie the many roles of macrophages in health and disease states in vivo remain poorly understood. The purpose of this Review is to present and discuss current knowledge on the developmental biology of macrophages, as it underlies the concept of a layered myeloid system composed of ‘resident’ macrophages that mostly originate from yolk sac progenitors and of ‘passenger’ or ‘transitory’ myeloid cells that originate and renew from bone marrow hematopoietic stem cells, and to provide a framework to investigate the functions of macrophages in vivo. PMID:26681456

  3. Macrophage Plasticity in Skeletal Muscle Repair

    PubMed Central

    Rigamonti, Elena; Sciorati, Clara; Rovere-Querini, Patrizia

    2014-01-01

    Macrophages are one of the first barriers of host defence against pathogens. Beyond their role in innate immunity, macrophages play increasingly defined roles in orchestrating the healing of various injured tissues. Perturbations of macrophage function and/or activation may result in impaired regeneration and fibrosis deposition as described in several chronic pathological diseases. Heterogeneity and plasticity have been demonstrated to be hallmarks of macrophages. In response to environmental cues they display a proinflammatory (M1) or an alternative anti-inflammatory (M2) phenotype. A lot of evidence demonstrated that after acute injury M1 macrophages infiltrate early to promote the clearance of necrotic debris, whereas M2 macrophages appear later to sustain tissue healing. Whether the sequential presence of two different macrophage populations results from a dynamic shift in macrophage polarization or from the recruitment of new circulating monocytes is a subject of ongoing debate. In this paper, we discuss the current available information about the role that different phenotypes of macrophages plays after injury and during the remodelling phase in different tissue types, with particular attention to the skeletal muscle. PMID:24860823

  4. Tissue-resident macrophages: then and now

    PubMed Central

    Davies, Luke C; Taylor, Philip R

    2015-01-01

    Macrophages have been at the heart of immune research for over a century and are an integral component of innate immunity. Macrophages are often viewed as terminally differentiated monocytic phagocytes. They infiltrate tissues during inflammation, and form polarized populations that perform pro-inflammatory or anti-inflammatory functions. Tissue-resident macrophages were regarded as differentiated monocytes, which seed the tissues to perform immune sentinel and homeostatic functions. However, tissue-resident macrophages are not a homogeneous population, but are in fact a grouping of cells with similar functions and phenotypes. In the last decade, it has been revealed that many of these cells are not terminally differentiated and, in most cases, are not derived from haematopoiesis in the adult. Recent research has highlighted that tissue-resident macrophages cannot be grouped into simple polarized categories, especially in vivo, when they are exposed to complex signalling events. It has now been demonstrated that the tissue environment itself is a major controller of macrophage phenotype, and can influence the expression of many genes regardless of origin. This is consistent with the concept that cells within different tissues have diverse responses in inflammation. There is still a mountain to climb in the field, as it evolves to encompass not only tissue-resident macrophage diversity, but also categorization of specific tissue environments and the plasticity of macrophages themselves. This knowledge provides a new perspective on therapeutic strategies, as macrophage subsets can potentially be manipulated to control the inflammatory environment in a tissue-specific manner. PMID:25684236

  5. Macrophages and HIV-1: An Unhealthy Constellation.

    PubMed

    Sattentau, Quentin J; Stevenson, Mario

    2016-03-01

    Lentiviruses have a long-documented association with macrophages. Abundant evidence exists for in vitro and, in a tissue-specific manner, in vivo infection of macrophages by the primate lentiviruses HIV-1 and SIV. However, macrophage contribution to aspects of HIV-1 and SIV pathogenesis, and their role in viral persistence in individuals on suppressive antiretroviral therapy, remains unclear. Here we discuss recent evidence implicating macrophages in HIV-1-mediated disease and highlight directions for further investigation. PMID:26962941

  6. Macrophage Polarization in Virus-Host Interactions

    PubMed Central

    Sang, Yongming; Miller, Laura C; Blecha, Frank

    2015-01-01

    Macrophage involvement in viral infections and antiviral states is common. However, this involvement has not been well-studied in the paradigm of macrophage polarization, which typically has been categorized by the dichotomy of classical (M1) and alternative (M2) statuses. Recent studies have revealed the complexity of macrophage polarization in response to various cellular mediators and exogenous stimuli by adopting a multipolar view to revisit the differential process of macrophages, especially those re-polarized during viral infections. Here, through examination of viral infections targeting macrophages/monocytic cells, we focus on the direct involvement of macrophage polarization during viral infections. Type I and type III interferons (IFNs) are critical in regulation of viral pathogenesis and host antiviral infection; thus, we propose to incorporate IFN-mediated antiviral states into the framework of macrophage polarization. This view is supported by the multifunctional properties of type I IFNs, which potentially elicit and regulate both M1- and M2-polarization in addition to inducing the antiviral state, and by the discoveries of viral mechanisms to adapt and modulate macrophage polarization. Indeed, several recent studies have demonstrated effective prevention of viral diseases through manipulation of macrophage immune statuses. PMID:26213635

  7. Changes in transcriptome of macrophages in atherosclerosis

    PubMed Central

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

    2015-01-01

    Macrophages display significant phenotypic heterogeneity. Two growth factors, macrophage colony-stimulating factor and chemokine (C-X-C motif) ligand 4, drive terminal differentiation of monocytes to M0 and M4 macrophages respectively. Compared to M0 macrophages, M4 cells have a unique transcriptome, with expression of surface markers such as S100A8, mannose receptor CD206 and matrix metalloproteinase 7. M4 macrophages did not express CD163, a scavenger receptor for haemoglobin/haptoglobin complex. Depending on the stimuli, M0 macrophages could polarize towards the proinflammatory M1 subset by treatment with lipopolysaccharide or interferon-γ. These macrophages produce a range of proinflammatory cytokines, nitric oxide, reactive oxygen species and exhibit high chemotactic and phagocytic activity. The alternative M2 type could be induced from M0 macrophage by stimulation with interleukin (IL)-4. M2 macrophages express high levels of CD206 and produce anti-inflammatory cytokines IL-10 and transforming growth factor-β. M1, M2 and M4 macrophages could be found in atherosclerotic plaques. In the plaque, macrophages are subjected to the intensive influence not only by cytokines and chemokines but also with bioactive lipids such as cholesterol and oxidized phospholipids. Oxidized phospholipids induce a distinct Mox phenotype in murine macrophages that express a unique panel of antioxidant enzymes under control of the redox-regulated transcription factor Klf2, resistant to lipid accumulation. In unstable human lesions, atheroprotective M(Hb) and HA-mac macrophage subsets could be found. These two subsets are induced by the haemoglobin/haptoglobin complex, highly express haeme oxygenase 1 and CD163, and are implicated in clearance of haemoglobin and erythrocyte remnants. In atherogenesis, the macrophage phenotype is plastic and could therefore be switched to proinflammatory (i.e. proatherogenic) and anti-inflammatory (i.e. atheroprotective). The aim of this review was to

  8. Radiological Defense Officer. Student Workbook.

    ERIC Educational Resources Information Center

    Defense Civil Preparedness Agency (DOD), Washington, DC.

    This student workbook includes the necessary administrative materials, briefs, exercises and answer sheets for the quizzes and final course examination as needed by the students during the conduct of the Radiological Defense Officer course. Among the briefs included are the following: (1) Reporting Forms; (2) Forecasting Dose Rates; (3) Dose…

  9. Directions for Defense Digital Libraries.

    ERIC Educational Resources Information Center

    Larsen, Ronald L.

    1998-01-01

    Describes directions, challenges, and objectives of the information management program of the United States Defense Advanced Research Projects Agency (DARPA). The program envisions the rigor and organization normally associated with a research library to be virtually rendered and extended in the networked world of distributed information. (AEF)

  10. In Defense of the Vendors

    ERIC Educational Resources Information Center

    Irwin, G. Brockett

    1975-01-01

    The problems that are encountered when cooperation breaks down between the industrial source operator and the pollution control equipment vendor are examined. The focal point of this examination is the study of defenses available to the equipment vendor when industrial source operators refuse to cooperate. (Author/BT)

  11. Collaborative Attack vs. Collaborative Defense

    NASA Astrophysics Data System (ADS)

    Xu, Shouhuai

    We have witnessed many attacks in the cyberspace. However, most attacks are launched by individual attackers even though an attack may involve many compromised computers. In this paper, we envision what we believe to be the next generation cyber attacks — collaborative attacks. Collaborative attacks can be launched by multiple attackers (i.e., human attackers or criminal organizations), each of which may have some specialized expertise. This is possible because cyber attacks can become very sophisticated and specialization of attack expertise naturally becomes relevant. To counter collaborative attacks, we might need collaborative defense because each “chain” in a collaborative attack may be only adequately dealt with by a different defender. In order to understand collaborative attack and collaborative defense, we present a high-level abstracted framework for evaluating the effectiveness of collaborative defense against collaborative attacks. As a first step towards realizing and instantiating the framework, we explore a characterization of collaborative attacks and collaborative defense from the relevant perspectives.

  12. Acute radiation syndrome (ARS) – treatment of the reduced host defense

    PubMed Central

    Heslet, Lars; Bay, Christiane; Nepper-Christensen, Steen

    2012-01-01

    Background The current radiation threat from the Fukushima power plant accident has prompted rethinking of the contingency plan for prophylaxis and treatment of the acute radiation syndrome (ARS). The well-documented effect of the growth factors (granulocyte colony-stimulating factor [G-CSF] and granulocyte-macrophage colony-stimulating factor [GM-CSF]) in acute radiation injury has become standard treatment for ARS in the United States, based on the fact that growth factors increase number and functions of both macrophages and granulocytes. Methods Review of the current literature. Results The lungs have their own host defense system, based on alveolar macrophages. After radiation exposure to the lungs, resting macrophages can no longer be transformed, not even during systemic administration of growth factors because G-CSF/GM-CSF does not penetrate the alveoli. Under normal circumstances, locally-produced GM-CSF receptors transform resting macrophages into fully immunocompetent dendritic cells in the sealed-off pulmonary compartment. However, GM-CSF is not expressed in radiation injured tissue due to defervescence of the macrophages. In order to maintain the macrophage’s important role in host defense after radiation exposure, it is hypothesized that it is necessary to administer the drug exogenously in order to uphold the barrier against exogenous and endogenous infections and possibly prevent the potentially lethal systemic infection, which is the main cause of death in ARS. Recommendation Preemptive treatment should be initiated after suspected exposure of a radiation dose of at least <2 Gy by prompt dosing of 250–400 μg GM-CSF/m2 or 5 μg/kg G-CSF administered systemically and concomitant inhalation of GM-CSF < 300 mcg per day for at least 14–21 days. Conclusion The present United States standard for prevention and treatment of ARS standard intervention should consequently be modified into the combined systemic administration of growth factors and

  13. Dihydro-CDDO-trifluoroethyl amide suppresses inflammatory responses in macrophages via activation of Nrf2

    SciTech Connect

    Li, Bin; Abdalrahman, Akram; Lai, Yimu; Janicki, Joseph S.; Ward, Keith W.; Meyer, Colin J.; Wang, Xing Li; Tang, Dongqi; Cui, Taixing

    2014-02-21

    Highlights: • Dh404 suppresses the expression of a selected set of pro-inflammatory cytokines in inflamed macrophages via activating Nrf2. • Dh404 activates Nrf2 while keeping Keap1 function intact in macrophages. • Dh404 minimally regulates NF-κB pathway in macrophages. - Abstract: Nuclear factor erythroid 2-related factor (Nrf2) is the major regulator of cellular defenses against various pathological stresses in a variety of organ systems, thus Nrf2 has evolved to be an attractive drug target for the treatment and/or prevention of human disease. Several synthetic oleanolic triterpenoids including dihydro-CDDO-trifluoroethyl amide (dh404) appear to be potent activators of Nrf2 and exhibit chemopreventive promises in multiple disease models. While the pharmacological efficacy of Nrf2 activators may be dependent on the nature of Nrf2 activation in specific cell types of target organs, the precise role of Nrf2 in mediating biological effects of Nrf2 activating compounds in various cell types remains to be further explored. Herein we report a unique and Nrf2-dependent anti-inflammatory profile of dh404 in inflamed macrophages. In lipopolysaccharide (LPS)-inflamed RAW264.7 macrophages, dh404 dramatically suppressed the expression of pro-inflammatory cytokines including inducible nitric oxide synthase (iNOS), monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1β), while minimally regulating the expression of interleulin-6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNFα). Dh404 potently activated Nrf2 signaling; however, it did not affect LPS-induced NF-κB activity. Dh404 did not interrupt the interaction of Nrf2 with its endogenous inhibitor Kelch-like ECH associating protein 1 (Keap1) in macrophages. Moreover, knockout of Nrf2 blocked the dh404-induced anti-inflammatory responses in LPS-inflamed macrophages. These results demonstrated that dh404 suppresses pro-inflammatory responses in macrophages via an activation

  14. Global Secretome Characterization of Herpes Simplex Virus 1-Infected Human Primary Macrophages

    PubMed Central

    Miettinen, Juho J.; Matikainen, Sampsa

    2012-01-01

    Herpes simplex virus 1 (HSV-1) is a common pathogen infecting the majority of people worldwide at some stage in their lives. The early host response to viral infection is initiated by the cells of the innate immune response, including macrophages. Here, we have characterized the secretome of HSV-1-infected human primary macrophages using high-throughput quantitative proteomics. We identified and quantified 516 distinct human proteins with high confidence from the macrophage secretome upon HSV-1 infection, and the secretion of 411 proteins was >2-fold increased upon beta interferon (IFN-β) priming and/or HSV-1 infection. Bioinformatics analysis of the secretome data revealed that most of the secreted proteins were intracellular, and almost 80% of the proteins whose secretion increased more than 2-fold were known exosomal proteins. This strongly suggests that nonclassical, vesicle-mediated protein secretion is activated in IFN-β-primed and HSV-1-infected macrophages. Proteins related to immune and inflammatory responses, interferon-induced proteins, and endogenous danger signal proteins were efficiently secreted upon IFN-β priming and HSV-1 infection. The secreted IFN-induced proteins include interferon-induced tetratricopeptide protein 2 (IFIT2), IFIT3, signal transducer and activator of transcription 1 (STAT1), and myxovirus resistance protein A (MxA), implicating that these proteins also have important extracellular antiviral functions. Proinflammatory cytokine interleukin-1β was not released by HSV-1-infected macrophages, demonstrating that HSV-1 can antagonize inflammasome function. In conclusion, our results provide a global view of the secretome of HSV-1-infected macrophages, revealing host factors possibly having a role in antiviral defense. PMID:22973042

  15. Mycobacterium tuberculosis Infection Induces HDAC1-Mediated Suppression of IL-12B Gene Expression in Macrophages.

    PubMed

    Chandran, Aneesh; Antony, Cecil; Jose, Leny; Mundayoor, Sathish; Natarajan, Krishnamurthy; Kumar, R Ajay

    2015-01-01

    Downregulation of host gene expression is one of the many strategies employed by intracellular pathogens such as Mycobacterium tuberculosis (MTB) to survive inside the macrophages and cause disease. The underlying molecular mechanism behind the downregulation of host defense gene expression is largely unknown. In this study we explored the role of histone deacetylation in macrophages in response to infection by virulent MTB H37Rv in manipulating host gene expression. We show a significant increase in the levels of HDAC1 with a concomitant and marked reduction in the levels of histone H3-acetylation in macrophages containing live, but not killed, virulent MTB. Additionally, we show that HDAC1 is recruited to the promoter of IL-12B in macrophages infected with live, virulent MTB, and the subsequent hypoacetylation of histone H3 suppresses the expression of this gene which plays a key role in initiating Th1 responses. By inhibiting immunologically relevant kinases, and by knockdown of crucial transcriptional regulators, we demonstrate that protein kinase-A (PKA), CREB, and c-Jun play an important role in regulating HDAC1 level in live MTB-infected macrophages. By chromatin immunoprecipitation (ChIP) analysis, we prove that HDAC1 expression is positively regulated by the recruitment of c-Jun to its promoter. Knockdown of HDAC1 in macrophages significantly reduced the survival of intracellular MTB. These observations indicate a novel HDAC1-mediated epigenetic modification induced by live, virulent MTB to subvert the immune system to survive and replicate in the host. PMID:26697414

  16. [Effect of cigarette smoke extract on phagocytosis of Staphylococcus aureus by macrophages].

    PubMed

    Ak, Sibel; Gürses, Serdar Abidin; Eser, Bekir Engin

    2016-04-01

    Staphylococcus aureus is one of the most important pathogen that causes community acquired and nosocomial infections worldwide. Phagocytosis by macrophages plays an important role in the first line defense against infections caused by S.aureus. On the other hand, the conducted studies have indicated that cigarette smoke has negative effects on both innate and acquired immune responses. The aim of this study was to investigate the effects of cigarette smoke on macrophage viability and their capacity of S.aureus phagocytosis. For this purpose THP-1 cell lines (human leukemic monocyte cell culture) were used and after the differentiation of the cells with PMA (phorbol myristate acetate) treatment, the macrophages were exposed to cigarette smoke extract (CSE) for 2- and 4-hours at concentrations of 1%, 5%, 10%, 25%, and 50%. Afterwards, the cells were stained with propidium iodide and the viability of the cells was analyzed by a flow cytometer. Two different methods were used to investigate the effect of CSE on the phagocytosis of S.aureus. The first one was the classical bacteriological method, in which macrophages were exposed to CSE for 2 hours in five different concentrations and were infected with 100 MOI (multiplicity of infection) S.aureus. After 1 hour of incubation, macrophages were lysed with PBS-0.1% Triton X-100 and plated on Luria-Bertani (LB) agar following serial dilutions. Newly formed colonies were counted and the number of bacteria phagocytosed were evaluated as colony forming units (CFU). The second method for the detection of phagocytosis was flow cytometric analysis in which SYBR(®) Green-labeled bacteria were used. To confirm that the macrophages were infected, bacteria were stained with SYBR(®) Green and macrophages were analyzed following infection via flow cytometry. Macrophages were exposed to 10% and 50% CSE and infected with bacteria stained with SYBR(®) Green. The level of phagocytosis was analyzed by flow cytometry in terms of median

  17. 76 FR 44293 - Defense Acquisition Regulations System; Defense Federal Acquisition Regulation Supplement; Only...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-25

    ... are in support of contingency, humanitarian, or peacekeeping operations, or to facilitate defense... peacekeeping operations, or to facilitate defense against or recovery from nuclear, biological, chemical,...

  18. Induction of Murine Macrophage M2 Polarization by Cigarette Smoke Extract via the JAK2/STAT3 Pathway

    PubMed Central

    Shi, Hengfei; Chen, Guopu; Dong, Ping; Zhang, Weiyun

    2014-01-01

    Cigarette smoking is a major pathogenic factor in lung cancer. Macrophages play an important role in host defense and adaptive immunity. These cells display diverse phenotypes for performing different functions. M2 type macrophages usually exhibit immunosuppressive and tumor-promoting characteristics. Although macrophage polarization toward the M2 phenotype has been observed in the lungs of cigarette smokers, the molecular basis of the process remains unclear. In this study, we evaluated the possible mechanisms for the polarization of mouse macrophages that are induced by cigarette smoking (CS) or cigarette smoke extract (CSE). The results showed that exposure to CSE suppressed the production of reactive oxygen species (ROS) and nitric oxide (NO) and down-regulated the phagocytic ability of Ana-1 cells. The CD163 expressions on the surface of macrophages from different sources were significantly increased in in vivo and in vitro studies. The M1 macrophage cytokines TNF-α, IL-12p40 and enzyme iNOS decreased in the culture supernatant, and their mRNA levels decreased depending on the time and concentration of CSE. In contrast, the M2 phenotype macrophage cytokines IL-10, IL-6, TGF-β1 and TGF-β2 were up-regulated. Moreover, phosphorylation of JAK2 and STAT3 was observed after the Ana-1 cells were treated with CSE. In addition, pretreating the Ana-1 cells with the STAT3 phosphorylation inhibitor WP1066 inhibited the CSE-induced CD163 expression, increased the mRNA level of IL-10 and significantly decreased the mRNA level of IL-12. In conclusion, we demonstrated that the M2 polarization of macrophages induced by CS could be mediated through JAK2/STAT3 pathway activation. PMID:25198511

  19. The Natural Cytotoxicity Receptor 1 Contribution to Early Clearance of Streptococcus pneumoniae and to Natural Killer-Macrophage Cross Talk

    PubMed Central

    Yossef, Rami; Hadad, Uzi; Elkabets, Moshe; Vallon-Eberhard, Alexandra; Hulihel, Luai; Jung, Steffen; Ghadially, Hormas; Braiman, Alex; Apte, Ron N.; Mandelboim, Ofer; Dagan, Ron; Mizrachi-Nebenzahl, Yaffa; Porgador, Angel

    2011-01-01

    Natural killer (NK) cells serve as a crucial first line of defense against tumors, viral and bacterial infections. We studied the involvement of a principal activating natural killer cell receptor, natural cytotoxicity receptor 1 (NCR1), in the innate immune response to S. pneumoniae infection. Our results demonstrate that the presence of the NCR1 receptor is imperative for the early clearance of S. pneumoniae. We tied the ends in vivo by showing that deficiency in NCR1 resulted in reduced lung NK cell activation and lung IFNγ production at the early stages of S. pneumoniae infection. NCR1 did not mediate direct recognition of S. pneumoniae. Therefore, we studied the involvement of lung macrophages and dendritic cells (DC) as the mediators of NK-expressed NCR1 involvement in response to S. pneumoniae. In vitro, wild type BM-derived macrophages and DC expressed ligands to NCR1 and co-incubation of S. pneumoniae-infected macrophages/DC with NCR1-deficient NK cells resulted in significantly lesser IFNγ levels compared to NCR1-expressing NK cells. In vivo, ablation of lung macrophages and DC was detrimental to the early clearance of S. pneumoniae. NCR1-expressing mice had more potent alveolar macrophages as compared to NCR1-deficient mice. This result correlated with the higher fraction of NCR1-ligandhigh lung macrophages, in NCR1-expressing mice, that had better phagocytic activity compared to NCR1-liganddull macrophages. Overall, our results point to the essential contribution of NK-expressed NCR1 in early response to S. pneumoniae infection and to NCR1-mediated interaction of NK and S. pneumoniae infected-macrophages and -DC. PMID:21887255

  20. Cuckoos combat socially transmitted defenses of reed warbler hosts with a plumage polymorphism.

    PubMed

    Thorogood, Rose; Davies, Nicholas B

    2012-08-01

    In predator-prey and host-parasite interactions, an individual's ability to combat an opponent often improves with experience--for example, by learning to identify enemy signals. Although learning occurs through individual experience, individuals can also assess threats from social information. Such recognition could promote the evolution of polymorphisms if socially transmitted defenses depend on enemy morph frequency. This would allow rare variants to evade detection. Female brood parasitic common cuckoos, Cuculus canorus, are either gray or rufous. The gray morph is a Batesian mimic whose hawk-like appearance deters host attack. Hosts reject this disguise through social learning, increasing their own defenses when they witness neighbors mobbing a cuckoo. Our experiments reveal that social learning is specific to the cuckoo morph that neighbors mob. Therefore, while neighbors alert hosts to local cuckoo activity, frequency-dependent social information selects for a cuckoo plumage polymorphism to thwart host detection. Our results suggest that selection for mimicry and polymorphisms comes not only from personal experience but also from social learning. PMID:22859487

  1. Defense of the lungs in oxygen-injured baboons

    SciTech Connect

    Fowler, S.R.; Rawlinson, W.K.; Roach, F.M.; Seidenfeld, J.J.

    1986-03-05

    Pneumonia and subsequent sepsis have been linked with multiple organ failure and death in patients with adult respiratory distress syndrome. This suggests that lung defense may be impaired. In a model of ARDS, 13 baboons were intubated and ventilated with 80% O/sub 2/ for 6 days, following which 7 were inoculated intratracheally with Pseudomonas aeruginosa (PA) strain DGI-RI30. After 5 days on 50% O/sub 2/ the animals were sacrificed. Bronchoalveolar lavage (BAL) was performed before O/sub 2/ exposure, after 6 days of 80% O/sub 2/, and at sacrifice. Total WBC and differential counts were determined for BAL cells. Mononuclear BAL cells were isolated for in vitro phagocytosis assays. BAL fluid (BALF) was tested for in vitro PMN chemotactic activity. An index of bacterial infection (sum of log CFU/g lung homogenate) was greater for infected animals (p < 0.01). Percentage of PMN in BALF was significantly increased at sacrifice in PA-inoculated animals. BALF from PA-inoculated animals at sacrifice elicited increased in vitro PMN chemotaxis, which was destroyed at 100/sup 0/C but not 56/sup 0/C, extracted by ether, and not degraded by proteases. Mononuclear BAL cells from inoculated animals at sacrifice were phagocytially more active than baseline cells. These data suggest that oxygen injury does not inhibit recruitment of PMN or phagocytosis of bacteria by alveolar macrophages in baboons; however, the addition of bacterial inoculation results in clinical deterioration despite unimpaired local defense.

  2. Role of Interleukin 36γ in Host Defense Against Tuberculosis.

    PubMed

    Ahsan, Fadhil; Moura-Alves, Pedro; Guhlich-Bornhof, Ute; Klemm, Marion; Kaufmann, Stefan H E; Maertzdorf, Jeroen

    2016-08-01

    Tuberculosis remains a major killer worldwide, not the least because of our incomplete knowledge of protective and pathogenic immune mechanism. The roles of the interleukin 1 (IL-1) and interleukin 18 pathways in host defense are well established, as are their regulation through the inflammasome complex. In contrast, the regulation of interleukin 36γ (IL-36γ), a recently described member of the IL-1 family, and its immunological relevance in host defense remain largely unknown. Here we show that Mycobacterium tuberculosis infection of macrophages induces IL-36γ production in a 2-stage-regulated fashion. In the first stage, microbial ligands trigger host Toll-like receptor and MyD88-dependent pathways, leading to IL-36γ secretion. In the second stage, endogenous IL-1β and interleukin 18 further amplify IL-36γ synthesis. The relevance of this cytokine in the control of M. tuberculosis is demonstrated by IL-36γ-induced antimicrobial peptides and IL-36 receptor-dependent restriction of M. tuberculosis growth. Thus, we provide first insight into the induction and regulation of the proinflammatory cytokine IL-36γ during tuberculosis. PMID:27389350

  3. Phosphorylation of immunity-related GTPases by a Toxoplasma gondii secreted kinase promotes macrophage survival and virulence

    PubMed Central

    Fentress, Sarah J.; Behnke, Michael S.; Dunay, Ildiko R.; Mashayekhi, Mona; Rommereim, Leah M.; Fox, Barbara A.; Bzik, David J.; Taylor, Gregory A.; Turk, Benjamin E.; Lichti, Cheryl F.; Townsend, R. Reid; Qiu, Wei; Hui, Raymond; Beatty, Wandy L.; Sibley, L. David

    2010-01-01

    SUMMARY Macrophages are specialized to detect and destroy intracellular microbes and yet a number of pathogens have evolved to exploit this hostile niche. Here we demonstrate that the obligate intracellular parasite Toxoplasma gondii disarms macrophage innate clearance mechanisms by secreting a serine threonine kinase called ROP18, which binds to and phosphorylates immunity-related GTPases (IRGs). Substrate profiling of ROP18 revealed a preference for a conserved motif within switch region I of the GTPase domain, a modification predicted to disrupt IRG function. Consistent with this, expression of ROP18 was both necessary and sufficient to block recruitment of Irgb6, which was in turn required for parasite destruction. ROP18 phosphorylation of IRGs prevented clearance within inflammatory monocytes and IFN-γ-activated macrophages, conferring parasite survival in vivo and promoting virulence. IRGs are implicated in clearance of a variety of intracellular pathogens, suggesting that other virulence factors may similarly thwart this innate cellular defense mechanism. PMID:21147463

  4. Phosphorylation of immunity-related GTPases by a Toxoplasma gondii-secreted kinase promotes macrophage survival and virulence.

    PubMed

    Fentress, Sarah J; Behnke, Michael S; Dunay, Ildiko R; Mashayekhi, Mona; Rommereim, Leah M; Fox, Barbara A; Bzik, David J; Taylor, Gregory A; Turk, Benjamin E; Lichti, Cheryl F; Townsend, R Reid; Qiu, Wei; Hui, Raymond; Beatty, Wandy L; Sibley, L David

    2010-12-16

    Macrophages are specialized to detect and destroy intracellular microbes and yet a number of pathogens have evolved to exploit this hostile niche. Here we demonstrate that the obligate intracellular parasite Toxoplasma gondii disarms macrophage innate clearance mechanisms by secreting a serine threonine kinase called ROP18, which binds to and phosphorylates immunity-related GTPases (IRGs). Substrate profiling of ROP18 revealed a preference for a conserved motif within switch region I of the GTPase domain, a modification predicted to disrupt IRG function. Consistent with this, expression of ROP18 was both necessary and sufficient to block recruitment of Irgb6, which was in turn required for parasite destruction. ROP18 phosphorylation of IRGs prevented clearance within inflammatory monocytes and IFN-γ-activated macrophages, conferring parasite survival in vivo and promoting virulence. IRGs are implicated in clearance of a variety of intracellular pathogens, suggesting that other virulence factors may similarly thwart this innate cellular defense mechanism. PMID:21147463

  5. Civil Defense, U. S. A.: A Programmed Orientation to Civil Defense. Unit 1. Civil Defense - Protection Against What?

    ERIC Educational Resources Information Center

    Defense Civil Preparedness Agency (DOD), Battle Creek, MI.

    An explanation of the need for civil defense in nuclear and natural disasters is presented. A brief historical background of civil defense is given. Major topics include: (1) Types of disasters, (2) Probable objectives of a nuclear attack on the United States, (3) The major defensive measures against a nuclear attack, (4) Some reasons for low…

  6. Purinergic signaling during macrophage differentiation results in M2 alternative activated macrophages.

    PubMed

    Barberà-Cremades, Maria; Baroja-Mazo, Alberto; Pelegrín, Pablo

    2016-02-01

    Macrophages represent a highly heterogenic cell population of the innate immune system, with important roles in the initiation and resolution of the inflammatory response. Purinergic signaling regulates both M1 and M2 macrophage function at different levels by controlling the secretion of cytokines, phagocytosis, and the production of reactive oxygen species. We found that extracellular nucleotides arrest macrophage differentiation from bone marrow precursors via adenosine and P2 receptors. This results in a mature macrophage with increased expression of M2, but not M1, genes. Similar to adenosine and ATP, macrophage growth arrested with LPS treatment resulted in an increase of the M2-related marker Ym1. Recombinant Ym1 was able to affect macrophage proliferation and could, potentially, be involved in the arrest of macrophage growth during hematopoiesis. PMID:26382298

  7. Macrophage activation by OM-85 BV.

    PubMed

    Mauël, J

    1992-01-01

    Peritoneal or bone-marrow-derived murine macrophages were exposed for 24 h in vitro to dilutions of the bacterial extract OM-85 BV, in the presence or absence of other added compounds [macrophage-activating factor (MAF), recombinant murine interferon-gamma (IFN-gamma)]. Various metabolic responses and functional activities were then measured. Glucose oxidation through the hexose monophosphate shunt pathway was markedly stimulated in OM-85 BV-treated macrophages compared to control macrophages. Similarly, OM-85 BV primed macrophages for superoxide production upon triggering by phorbol myristate acetate. Both effects were further enhanced by simultaneous treatment of the cells with MAF with OM-85 BV. The bacterial extract also induced macrophages to release large amounts of nitrite (a marker of the activated state). As regards functional responses, coincubation with MAF and OM-85 BV activated macrophages to destroy target cells as well as intracellular microorganisms; in the latter case, similar results were obtained when MAF was replaced by IFN-gamma. In all these tests, the possibility that the observed effects were due to contamination of the bacterial extracts by endotoxin could be excluded. The above results indicate that OM-85 BV induces metabolic and functional properties in macrophages that are characteristic of the activated state and are important for host defence. PMID:1332156

  8. Rewiring macrophages for anti-tumour immunity.

    PubMed

    Lee, Yunqin; Biswas, Subhra K

    2016-06-28

    Tumour-associated macrophages facilitate cancer progression, but whether they can be reprogrammed to elicit an anti-tumour response remains unclear. Deletion of the microRNA-processing enzyme Dicer is now shown to rewire macrophages to an anti-tumour mode, leading to an enhanced response to immunotherapy and inhibition of tumour progression. PMID:27350442

  9. The Alternative Faces of Macrophage Generate Osteoclasts.

    PubMed

    Lampiasi, N; Russo, R; Zito, F

    2016-01-01

    The understanding of how osteoclasts are generated and whether they can be altered by inflammatory stimuli is a topic of particular interest for osteoclastogenesis. It is known that the monocyte/macrophage lineage gives rise to osteoclasts (OCs) by the action of macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor-kB ligand (RANKL), which induce cell differentiation through their receptors, c-fms and RANK, respectively. The multinucleated giant cells (MGCs) generated by the engagement of RANK/RANKL are typical OCs. Nevertheless, very few studies have addressed the question of which subset of macrophages generates OCs. Indeed, two main subsets of macrophages are postulated, the inflammatory or classically activated type (M1) and the anti-inflammatory or alternatively activated type (M2). It has been proposed that macrophages can be polarized in vitro towards a predominantly M1 or M2 phenotype with the addition of granulocyte macrophage- (GM-) CSF or M-CSF, respectively. Various inflammatory stimuli known to induce macrophage polarization, such as LPS or TNF-α, can alter the type of MGC obtained from RANKL-induced differentiation. This review aims to highlight the role of immune-related stimuli and factors in inducing macrophages towards the osteoclastogenesis choice. PMID:26977415

  10. Synthesis of Dipalmitoyl Lecithin by Alveolar Macrophages

    PubMed Central

    Mason, Robert J.; Huber, Gary; Vaughan, Martha

    1972-01-01

    A reliable, relatively simple method for isolation and quantification of disaturated lecithins is described. In rabbit lung, 34% of the lecithins were disaturated, in alveolar macrophages, 19%. More than 95% of the fatty acids of the disaturated lecithins from lung and alveolar macrophages was palmitic. Hence, the disaturated lecithins from these sources were essentially all dipalmitoyl lecithin. Both heterophils and alveolar macrophages incorporated 14C-labeled choline and palmitate into disaturated lecithins. Liver slices in which only about 1% of the lecithins were disaturated incorporated very little of these precursors into this fraction. Of the palmitate incorporated in vitro into disaturated lecithins by alveolar macrophages, heterophils, and lung slices, 37% was in the 1 position. In disaturated lecithins isolated from pulmonary lavage fluid, alveolar macrophages, and lung of rabbit 8-12 hr after a single intravenous injection of palmitic-1-14C acid, 45% of the 14C was in position 1. At earlier times, from 20-240 min after injection, the distribution of 14C was similar in the samples from lung, but in those from alveolar macrophages and lavage fluid, the percentage in position 1 was slightly lower. Glycerol-U-14C was incorporated into disaturated lecithins by alveolar macrophages and by lung slices in vitro. Both tissues incorporated very little label from ethanolamine or from methyl-labeled methionine into this fraction. All of the data are consistent with the view that alveolar macrophages synthesize dipalmitoyl lecithin via the cytidine diphosphate-choline pathway. PMID:5066597

  11. Macrophage polarization in virus-host interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Macrophage involvement in viral infections and antiviral states is common. However, this involvement has not been well-studied in the paradigm of macrophage polarization, which typically has been categorized by the dichotomy of classical (M1) and alternative (M2) statuses. Recent studies have reveal...

  12. Acute exposure to methamphetamine alters TLR9-mediated cytokine expression in human macrophage.

    PubMed

    Burns, Ariel; Ciborowski, Pawel

    2016-02-01

    Recent studies show that methamphetamine (Meth) use leads to higher susceptibility to and progression of infections, which suggests impairment of the immune system. The first line of defense against infections is the innate immune system and the macrophage is a key player in preventing and fighting infections. So we profiled cytokines over time in Meth treated THP-1 cells, as a human macrophage model, at a relevant concentration using high throughput screening to find a signaling target. We showed that after a single exposure, the effect of Meth on macrophage cytokine production was rapid and time dependent and shifted the balance of expression of cytokines to pro-inflammatory. Our results were analogous to previous reports in that Meth up-regulates TNF-α and IL-8 after two hours of exposure. However, global screening led to the novel identification of CXCL16, CXCL1 and many other up-regulated cytokines. We also showed CCL7 as the most down-regulated chemokine due to Meth exposure, which led us to hypothesize that Meth dysregulates the MyD88-dependent Toll-like receptor 9 (TLR9) signaling pathway. In conclusion, altered cytokine expression in macrophages suggests it could lead to a suppressed innate immunity in people who use Meth. PMID:26387832

  13. Modulation of macrophage functionality induced in vitro by chlorpyrifos and carbendazim pesticides.

    PubMed

    Helali, Imen; Ferchichi, Saiida; Maaouia, Amal; Aouni, Mahjoub; Harizi, Hedi

    2016-09-01

    The immune response is the first defense against pathogens; however, it is very sensitive and can be impacted on by agrochemicals such as carbamate and organophosphate pesticides widely present in the environment. To understand how pesticides can affect immune cell function in vitro, this study investigated the effects of chlorpyrifos (CPF) and carbendazim (CBZ), the most commonly used pesticides worldwide, on murine immune cell (i.e. macrophage) functions, including lysosomal enzyme activity and pro-inflammatory cytokines (IL-1β and TNFα) and nitric oxide (NO) production by isolated mouse peritoneal macrophages. This study showed for the first time that CPF and CBZ dose-relatedly reduced macrophage lysosomal enzyme activity and LPS-induced production of IL-1β, TNFα and NO. In general, the effects caused by CPF appeared more pronounced than those by CBZ. Collectively, these results demonstrated that CPF and CBZ exhibited marked immunomodulatory effects and could act as potent immunosuppressive factors in vitro. This inhibition of macrophage pro-inflammatory function may be an integral part of the underlying mode of action related to pesticide-induced immunosuppression. PMID:27429139

  14. Contribution of Lung Macrophages to the Inflammatory Responses Induced by Exposure to Air Pollutants

    PubMed Central

    van Eeden, Stephan F.

    2013-01-01

    Large population cohort studies have indicated an association between exposure to particulate matter and cardiopulmonary morbidity and mortality. The inhalation of toxic environmental particles and gases impacts the innate and adaptive defense systems of the lung. Lung macrophages play a critically important role in the recognition and processing of any inhaled foreign material such as pathogens or particulate matter. Alveolar macrophages and lung epithelial cells are the predominant cells that process and remove inhaled particulate matter from the lung. Cooperatively, they produce proinflammatory mediators when exposed to atmospheric particles. These mediators produce integrated local (lung, controlled predominantly by epithelial cells) and systemic (bone marrow and vascular system, controlled predominantly by macrophages) inflammatory responses. The systemic response results in an increase in the release of leukocytes from the bone marrow and an increased production of acute phase proteins from the liver, with both factors impacting blood vessels and leading to destabilization of existing atherosclerotic plaques. This review focuses on lung macrophages and their role in orchestrating the inflammatory responses induced by exposure to air pollutants. PMID:24058272

  15. Virulent Mycobacterium bovis Beijing Strain Activates the NLRP7 Inflammasome in THP-1 Macrophages

    PubMed Central

    Zhou, Yang; Shah, Syed Zahid Ali; Yang, Lifeng; Zhang, Zhongqiu; Zhou, Xiangmei; Zhao, Deming

    2016-01-01

    Mycobacterium bovis is the causative agent of tuberculosis in a wide range of mammals, including humans. Macrophages are the first line of host defense. They secrete proinflammatory cytokines, such as interleukin-1 beta (IL-1β), in response to mycobacterial infection, but the underlying mechanisms by which human macrophages are activated and release IL-1β following M. bovis infection are poorly understood. Here we show that the ‘nucleotide binding and oligomerization of domain-like receptor (NLR) family pyrin domain containing 7 protein’ (NLRP7) inflammasome is involved in IL-1β secretion and caspase-1 activation induced by M. bovis infection in THP-1 macrophages. NLRP7 inflammasome activation promotes the induction of pyroptosis as well as the expression of tumor necrosis factor alpha (TNF-α), Chemokine (C-C motif) ligand 3 (CCL3) and IL-1β mRNAs. Thus, the NLRP7 inflammasome contributes to IL-1β secretion and induction of pyroptosis in response to M. bovis infection in THP-1 macrophages. PMID:27043315

  16. The role of macrophages in obesity-driven chronic liver disease.

    PubMed

    Devisscher, Lindsey; Verhelst, Xavier; Colle, Isabelle; Van Vlierberghe, Hans; Geerts, Anja

    2016-05-01

    Overnutrition and a sedentary lifestyle have resulted in the expansion of human obesity and associated metabolic complications. Nonalcoholic fatty liver disease has become the most common chronic liver disease in Western developed countries and can range from simple hepatic steatosis to a combination of steatosis, inflammation, and ballooning degeneration (nonalcoholic steatohepatitis). Obesity and its related liver disease are both risk factors for hepatocellular carcinoma, the incidence of which is expected to increase rapidly. The pathogenesis of nonalcoholic fatty liver disease and its progression to nonalcoholic steatohepatitis and hepatocellular carcinoma involve a deregulated lipid metabolism and a disruption of immune homeostasis and tissue integrity and are associated with a state of chronic inflammation. Macrophages are immune cells essential for maintenance of organ function and homeostasis but can also contribute to tissue damage and maintain a proinflammatory response. Their function depends on their origin, and tissue and can be converted based on local environmental cues. Resident liver macrophages, Kupffer cells, which function as sentinels, provide a first defense and are assisted by infiltrating monocytes in cases of hepatic insult. Until now, the contribution of tissue-residing and infiltrating macrophages to the onset and progression of nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, and hepatocellular carcinoma has been only partially unraveled. This review summarizes the current knowledge on the contribution of macrophage subsets to obesity-driven fatty liver disease and its complications and sheds light on still unexplored areas. PMID:26936934

  17. Leishmania donovani secretory serine protease alters macrophage inflammatory response via COX-2 mediated PGE-2 production.

    PubMed

    Das, Partha; De, Tripti; Chakraborti, Tapati

    2014-12-01

    Leishmania parasites determine the outcome of the infection by inducing inflammatory response that suppresses macrophage's activation. Defense against Leishmania is dependent on Th1 inflammatory response by turning off macrophages' microbicidal property by upregulation of COX-2, as well as immunosuppressive PGE-2 production. To understand the role of L. donovani secretory serine protease (pSP) in these phenomena, pSP was inhibited by its antibody and serine protease inhibitor, aprotinin. Western blot and TAME assay demonstrated that pSP antibody and aprotinin significantly inhibited protease activity in the live Leishmania cells and reduced infection index of L. donovani-infected macrophages. Additionally, ELISA and RT-PCR analysis showed that treatment with pSP antibody or aprotinin hold back COX-2-mediated immunosuppressive PGE-2 secretion with enhancement of Th1 cytokine like IL-12 expression. This was also supported in Griess test and NBT assay, where inhibition of pSP with its inhibitors elevated ROS and NO production. Overall, our study implies the pSP is involved in down-regulation of macrophage microbicidal activity by inducing host inflammatory responses in terms of COX-2-mediated PGE-2 release with diminished reactive oxygen species generation and thus suggests its importance as a novel drug target of visceral leishmaniasis. PMID:25823228

  18. Elaboration of Sterically Stabilized Liposomes for S-Nitrosoglutathione Targeting to Macrophages.

    PubMed

    Diab, R; Virriat, A S; Ronzani, C; Fontanay, S; Grandemange, S; Elaissari, A; Foliguet, B; Maincent, P; Leroy, P; Duvaj, R E; Rihn, B H; Joubert, O

    2016-01-01

    S-nitrosoglutathione (GSNO) is a potential therapeutic for infectious disease treatment because of its pivotal role in macrophage-mediated inflammatory responses and host defense in addition to direct antibacterial activities. In this study, sterically stabilized cationic liposomes (SSCL) and sterically stabilized anionic liposomes (SSAL) were developed as nanocarriers for macrophage targeting. Elaborated liposomes were characterized in terms of size, zeta potential, morphology, encapsulation efficiency, in vitro drug release behavior and cytotoxicity. Their versatility in targeting monocytes/macrophages was determined by confocal laser scanning microscopy and transmission electron microscopy. Flow cytometry revealed that cellular uptake of both SSCL and SSAL was governed by several endocytic clathrin- and caveolae-dependent mechanisms. Quantitative assessments of intracellular nitric oxide demonstrated highly efficient uptake of GSNO-loaded SSCL that was twenty-fold higher than that of GSNO-free molecules. GSNO-loaded SSCL displayed strong bacteriostatic effects on Staphylococcus aureus and Pseudomonas aeruginosa, which can be involved in pulmonary infectious diseases. These results reveal the potential of liposomal GSNO as an anti-infective therapeutic due to its macrophage targeting capacity and direct antibacterial effects. PMID:27301185

  19. Induction of heme oxygenase-1 by chamomile protects murine macrophages against oxidative stress

    PubMed Central

    Bhaskaran, Natarajan; Shukla, Sanjeev; Kanwal, Rajnee; Srivastava, Janmejai K; Gupta, Sanjay

    2012-01-01

    Aims Protection of cells from oxidative insult may be possible through direct scavenging of reactive oxygen species, or through stimulation of intracellular antioxidant defense mechanisms by induction of antioxidant gene expression. In this study we investigated the cytoprotective effect of chamomile and elucidated the underlying mechanisms. Main Methods The cytoprotective effect of chamomile was examined on H2O2-induced cellular stress in RAW 264.7 murine macrophages. Key Findings RAW 264.7 murine macrophages treated with chamomile were protected from cell death caused by H2O2. Treatment with 50 μM H2O2 for 6 h caused significant increase in cellular stress accompanied by cell death in RAW 264.7 macrophages. Pretreatment with chamomile at 10-20 μg/mL for 16 h followed by H2O2 treatment protected the macrophages against cell death. Chamomile exposure significantly increased the expression of antioxidant enzymes viz. heme oxygenase-1 (HO-1), peroxiredoxin-1 (Prx-1), and thioredoxin-1 (Trx-1) in a dose-dependent manner, compared with their respective controls. Chamomile increased nuclear translocation of Nrf2 with increased phosphorylated Nrf2 levels, and binding to the antioxidant response element in the nucleus. Significance These molecular findings for the first time provide insights into the mechanisms underlying the induction of phase 2 enzymes through the Keap1-Nrf2 signaling pathway by chamomile, and provide evidence that chamomile possesses antioxidant and cytoprotective properties. PMID:22683429

  20. 32 CFR 28.500 - Secretary of Defense.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Secretary of Defense. 28.500 Section 28.500 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT REGULATIONS NEW RESTRICTIONS ON LOBBYING Exemptions § 28.500 Secretary of Defense. (a) Exemption authority. The Secretary of Defense may exempt, on...

  1. An Evolutionarily Conserved PLC-PKD-TFEB Pathway for Host Defense.

    PubMed

    Najibi, Mehran; Labed, Sid Ahmed; Visvikis, Orane; Irazoqui, Javier Elbio

    2016-05-24

    The mechanisms that tightly control the transcription of host defense genes have not been fully elucidated. We previously identified TFEB as a transcription factor important for host defense, but the mechanisms that regulate TFEB during infection remained unknown. Here, we used C. elegans to discover a pathway that activates TFEB during infection. Gene dkf-1, which encodes a homolog of protein kinase D (PKD), was required for TFEB activation in nematodes infected with Staphylococcus aureus. Conversely, pharmacological activation of PKD was sufficient to activate TFEB. Furthermore, phospholipase C (PLC) gene plc-1 was also required for TFEB activation, downstream of Gαq homolog egl-30 and upstream of dkf-1. Using reverse and chemical genetics, we discovered a similar PLC-PKD-TFEB axis in Salmonella-infected mouse macrophages. In addition, PKCα was required in macrophages. These observations reveal a previously unknown host defense signaling pathway, which has been conserved across one billion years of evolution. PMID:27184844

  2. Mycobacteria, Metals, and the Macrophage

    PubMed Central

    Niederweis, Michael; Wolschendorf, Frank; Mitra, Avishek; Neyrolles, Olivier

    2015-01-01

    Summary Mycobacterium tuberculosis is a facultative intracellular pathogen that thrives inside host macrophages. A key trait of M. tuberculosis is to exploit and manipulate metal cation trafficking inside infected macrophages to ensure survival and replication inside the phagosome. Here we describe the recent fascinating discoveries that the mammalian immune system responds to infections with M. tuberculosis by overloading the phagosome with copper and zinc, two metals which are essential nutrients in small quantities but are toxic in excess. M. tuberculosis has developed multi-faceted resistance mechanisms to protect itself from metal toxicity including control of uptake, sequestration inside the cell, oxidation, and efflux. The host response to infections combines this metal poisoning strategy with nutritional immunity mechanisms that deprive M. tuberculosis from metals such as iron and manganese to prevent bacterial replication. Both immune mechanisms rely on the translocation of metal transporter proteins to the phagosomal membrane during the maturation process of the phagosome. This review summarizes these recent findings and discusses how metal-targeted approaches might complement existing TB chemotherapeutic regimens with novel anti-infective therapies. PMID:25703564

  3. Macrophagic myofasciitis: characterization and pathophysiology.

    PubMed

    Gherardi, R K; Authier, F J

    2012-02-01

    Aluminium oxyhydroxide (alum), a nanocrystalline compound forming agglomerates, has been used in vaccines for its immunological adjuvant effect since 1927. Alum is the most commonly used adjuvant in human and veterinary vaccines, but the mechanisms by which it stimulates immune responses remain incompletely understood. Although generally well tolerated, alum may occasionally cause disabling health problems in presumably susceptible individuals. A small proportion of vaccinated people present with delayed onset of diffuse myalgia, chronic fatigue and cognitive dysfunction, and exhibit very long-term persistence of alum-loaded macrophages at the site of previous intramuscular (i.m.) immunization, forming a granulomatous lesion called macrophagic myofasciitis (MMF). Clinical symptoms associated with MMF are paradigmatic of the recently delineated 'autoimmune/inflammatory syndrome induced by adjuvants' (ASIA). The stereotyped cognitive dysfunction is reminiscent of cognitive deficits described in foundry workers exposed to inhaled Al particles. Alum safety concerns will largely depend on whether the compound remains localized at the site of injection or diffuses and accumulates in distant organs. Animal experiments indicate that biopersistent nanomaterials taken up by monocyte-lineage cells in tissues, such as fluorescent alum surrogates, can first translocate to draining lymph nodes, and thereafter circulate in blood within phagocytes and reach the spleen, and, eventually, slowly accumulate in the brain. PMID:22235051

  4. Defense display strategy and roadmaps

    NASA Astrophysics Data System (ADS)

    Hopper, Darrel G.

    2002-08-01

    The Department of Defense (DoD) is developing a new strategy for displays. The new displays science and technology roadmap will incorporate urgent warfighter needs as well as investment opportunities where military advantage is foreseen. Thrusts now ending include the High Definition System (HDS) program and related initiatives, like flexible displays, at the Defense Advanced Research Projects Agency (DARPA). Continuing thrusts include a variety of Serviceled programs to develop micro-displays for virtual image helmet-/rifle-mounted systems for pilots and soldiers, novel displays, materials, and basic research. New thrusts are being formulated for ultra-resolution, true 3D, and intelligent displays (integration of computers and communication functions into screens). The new strategy is Service-led.

  5. Issues in national missile defense

    SciTech Connect

    Canavan, G.H.

    1998-12-01

    Strategic missiles and weapons are proliferating rapidly; thus, the US and its Allies are likely to face both capable bilateral threats and multilateral configurations with complex coalitions for which defenses could be essential for stability. Current hit-to-kill interceptor and radar and infrared detection, track, and discrimination technology should suffice for limited threats, but it is necessary to meet those threats in time while maintaining growth potential for the more sophisticated threats likely to follow. National Missile Defense faces a confusing array of threats, programs, and alternatives, but the technologies in development are clearly an appropriate first step towards any of them. They are likely to succeed in the near term; the challenge is to retain flexibility to provide needed options in the mid and long terms.

  6. Homeland Security and Defense Applications

    SciTech Connect

    2014-11-06

    Homeland Security and Defense Applications personnel are the best in the world at detecting and locating dirty bombs, loose nukes, and other radiological sources. The site trains the Nation's emergency responders, who would be among the first to confront a radiological or nuclear emergency. Homeland Security and Defense Applications highly training personnel, characterize the threat environment, produce specialized radiological nuclear detection equipment, train personnel on the equipment and its uses, test and evaluate the equipment, and develop different kinds of high-tech equipment to defeat terrorists. In New York City for example, NNSS scientists assisted in characterizing the radiological nuclear environment after 9/11, and produced specialized radiological nuclear equipment to assist local officials in their Homeland Security efforts.

  7. Homeland Security and Defense Applications

    ScienceCinema

    None

    2015-01-09

    Homeland Security and Defense Applications personnel are the best in the world at detecting and locating dirty bombs, loose nukes, and other radiological sources. The site trains the Nation's emergency responders, who would be among the first to confront a radiological or nuclear emergency. Homeland Security and Defense Applications highly training personnel, characterize the threat environment, produce specialized radiological nuclear detection equipment, train personnel on the equipment and its uses, test and evaluate the equipment, and develop different kinds of high-tech equipment to defeat terrorists. In New York City for example, NNSS scientists assisted in characterizing the radiological nuclear environment after 9/11, and produced specialized radiological nuclear equipment to assist local officials in their Homeland Security efforts.

  8. Second line of defense program

    SciTech Connect

    Cantut, L; Thomas, L L

    1999-07-15

    Since the collapse of the Soviet Union, the prospect of nuclear materials entering the world market has become an ever-increasing threat. The Second Line of Defense (SLD) program was developed by the U.S. Department of Energy's (DOE) Nuclear Transfer and Supplier Policy Division (NN-43) to assist the Russian Federation State Customs Committee (RFSCC) in strengthening its capability to prevent illicit trafficking of nuclear materials across Russia's borders. The SLD program is a natural complement to the Material Protection Control and Accounting (MPC and A) program, which represents a first line of defense against the theft and diversion of nuclear materials. The SLD program is the first U.S.-Russian cooperative program to combat the illicit trafficking of nuclear and nuclear-related materials to would-be proliferators across Russia's borders.

  9. Macrophage Polarization in Health and Disease

    PubMed Central

    Cassetta, Luca; Cassol, Edana; Poli, Guido

    2011-01-01

    Macrophages are terminally differentiated cells of the mononuclear phagocyte system that also encompasses dendritic cells, circulating blood monocytes, and committed myeloid progenitor cells in the bone marrow. Both macrophages and their monocytic precursors can change their functional state in response to microenvironmental cues exhibiting a marked heterogeneity. However, there are still uncertainties regarding distinct expression patterns of surface markers that clearly define macrophage subsets, particularly in the case of human macrophages. In addition to their tissue distribution, macrophages can be functionally polarized into M1 (proinflammatory) and M2 (alternatively activated) as well as regulatory cells in response to both exogenous infections and solid tumors as well as by systems biology approaches. PMID:22194670

  10. ROCK inhibition impedes macrophage polarity and functions.

    PubMed

    Liu, Yianzhu; Tejpal, Neelam; You, Junping; Li, Xian C; Ghobrial, Rafik M; Kloc, Malgorzata

    2016-02-01

    Macrophages play an important role in immune responses including allograft rejection and they are one of the potential targets of anti-rejection therapies in organ transplantation. Macrophage alloreactivity relies on their phenotype/polarity, motility, phagocytosis and matrix degradation, which in turn depend on proper functioning of actin cytoskeleton and its regulators, the small GTPase RhoA and its downstream effector the Rho-associated protein kinase (ROCK). Several laboratories showed that administration of ROCK inhibitor Y-27632 to the graft recipient inhibits chronic rejection or rodent cardiac allografts. Here we studied the effect of Y-27632 on mouse peritoneal macrophage structure, polarity and functions in in vitro assays. We show that Y-27632 inhibitor affects macrophage phenotype/polarity, phagocytosis, migration, and matrix degradation. These novel findings suggest that the impediment of macrophage structure and function via interference with the RhoA/ROCK pathway has a potential to be therapeutically effective in organ transplantation. PMID:26711331

  11. Protective and pathogenic functions of macrophage subsets.

    PubMed

    Murray, Peter J; Wynn, Thomas A

    2011-11-01

    Macrophages are strategically located throughout the body tissues, where they ingest and process foreign materials, dead cells and debris and recruit additional macrophages in response to inflammatory signals. They are highly heterogeneous cells that can rapidly change their function in response to local microenvironmental signals. In this Review, we discuss the four stages of orderly inflammation mediated by macrophages: recruitment to tissues; differentiation and activation in situ; conversion to suppressive cells; and restoration of tissue homeostasis. We also discuss the protective and pathogenic functions of the various macrophage subsets in antimicrobial defence, antitumour immune responses, metabolism and obesity, allergy and asthma, tumorigenesis, autoimmunity, atherosclerosis, fibrosis and wound healing. Finally, we briefly discuss the characterization of macrophage heterogeneity in humans. PMID:21997792

  12. Effect of hydroxyapatite microcrystals on macrophage activity.

    PubMed

    Fukuchi, N; Akao, M; Sato, A

    1995-01-01

    Hydroxyapatite (HAp) microcrystals were synthesized by a neutralization reaction of Ca(OH)2 suspension and H3PO4 solution using an ultrasonic homogenizer. The in vitro interaction of HAp microcrystals with rat peritoneal macrophages was investigated by measuring the viability, acid phosphatase (ACP) activity, lactate dehydrogenase (LDH) activity and intracellular calcium content. HAp calcined at 800 degrees C and alpha-alumina particles (alumina) were used as comparative materials. Macrophages actively phagocytosed HAp microcrystals by dissolving them. However, no damage in macrophages exposed to HAp microcrystals was observed by transmission electron microscopy. Macrophages in the presence of HAp microcrystals showed less ACP and LDH activity and higher intracellular calcium content than those in the presence of calcined HAp and alumina. HAp microcrystals had excellent biocompatibility to macrophages as well as sintered HAp. PMID:8785507

  13. Functional alterations in macrophages after hypoxia selection.

    PubMed

    Degrossoli, Adriana; Giorgio, Selma

    2007-01-01

    Regions of low oxygen tension are common features of inflamed and infected tissues and provide physiologic selective pressure for the expansion of cells with enhanced hypoxia tolerance. The aim of this study was to investigate whether macrophages resistant to death induced by hypoxia were accompanied by functional alterations. A mouse macrophage cell line (J774 cells) was used to obtain subpopulations of death-resistant macrophages induced by long-term exposure to severe hypoxia (<1% O(2)). The results indicated that exposing J774 macrophages to periods of severe hypoxia results in the selection of cells with phenotypes associated with the modulation of heat-shock protein 70 kDa (HSP70) expression, tumor necrosis factor-alpha (TNF-alpha), and nitric oxide (NO) production and reduced susceptibility to parasite Leishmania infection. Thus, we suggest that hypoxia-selected macrophages may influence the outcome of inflammation and infection. PMID:17202589

  14. Defense Programs Transportation Risk Assessment

    SciTech Connect

    Clauss, D.B.

    1994-08-01

    This paper provides an overview of the methodology used in a probabilistic transportation risk assessment conducted to assess the probabilities and consequences of inadvertent dispersal of radioactive materials arising from severe transportation accidents. The model was developed for the Defense Program Transportation Risk Assessment (DPTRA) study. The analysis incorporates several enhancements relative to previous risk assessments of hazardous materials transportation including newly-developed statistics on the frequencies and severities of tractor semitrailer accidents and detailed route characterization using the 1990 Census data.

  15. Stability of missile forces and defenses

    SciTech Connect

    Canavan, G.H.

    1997-04-01

    This note derives the exchange equation for mixes of missiles and defenses and discusses the impact on stability of varying their relative proportions. For fixed offenses increasing defenses decreases stability until first strikes fall to zero. The same is true of decreasing offenses for fixed defenses, although the decrease in indices is smaller. A judicious increase in defenses and decrease in offenses should effect that transition with minimum loss of stability.

  16. Glutathione Reductase Is Essential for Host Defense against Bacterial Infection

    PubMed Central

    Yan, Jing; Ralston, Melissa M.; Meng, Xiaomei; Bongiovanni, Kathleen D.; Jones, Amanda L.; Benndorf, Rainer; Nelin, Leif D.; Frazier, W. Joshua; Rogers, Lynette K.; Smith, Charles V.; Liu, Yusen

    2013-01-01

    Glutathione reductase (Gsr)1 catalyzes the reduction of glutathione disulfide to glutathione, a major cellular antioxidant. We have recently shown that Gsr is essential for host defense against the Gram-negative bacteria Escherichia coli in a mouse model of sepsis. While we have demonstrated that Gsr is required for sustaining the oxidative burst and the development of neutrophil extracellular traps, the role of Gsr in other phagocytic functions remains unclear. It is also unclear whether Gsr-deficient mice exhibit host defense defects against Gram-positive bacteria. In the present study, we characterized the effects of Gsr deficiency on the innate immune responses to a Gram-positive bacterium, group B Streptococcus, and to the Gram-negative bacterial cell wall component lipopolysaccharide (LPS). We found that like, E. coli, group B Streptococcus resulted in a substantially more robust cytokine response and a markedly higher morbidity and mortality in Gsr-deficient mice than in wildtype mice. The increased morbidity and mortality were associated with greater bacterial burden in the Gsr-deficient mice. Interestingly, Gsr-deficient mice did not exhibit a greater sensitivity to LPS than did wildtype mice. Analysis of the neutrophils of Gsr-deficient mice revealed impaired phagocytosis. In response to thioglycollate stimulation, Gsr-deficient mice mobilized far fewer phagocytes, including neutrophils, macrophages, and eosinophils, into their peritoneal cavities than did wildtype mice. The defective phagocyte mobilization is associated with profound oxidation and aggregation of ascitic proteins, particularly albumin. Our results indicate that the oxidative defense mechanism mediated by Gsr is required for an effective innate immune response against bacteria, likely by preventing phagocyte dysfunction due to oxidative damage. PMID:23623936

  17. Problems of National Missile Defense

    NASA Astrophysics Data System (ADS)

    Cornwall, John

    2000-04-01

    The currently-proposed national missile defense (NMD) is supposed to counter accidental Russian or Chinese launches of intercontinental nuclear-armed missiles, or rogue nation launches of similar nuclear missiles or of missiles armed with biological weapons, by using mid-course hit-to-kill vehicles guided by IR and radar. But it seems very likely that any nation capable of building (or buying) such a missile offense can build (or buy) effective countermeasures to NMD. These include anti-simulation decoys made of multi-layer insulation (MLI), with warheads covered in MLI sheaths so their signatures resemble those of the decoys. MLI can be effective against both passive IR and radar detection/discrimination. Biological warheads can counter any mid-course defense by releasing a great number of submunitions early in flight. Both nuclear and biological weapons can be deployed by other means, including covert ships in port; trucks; and cruise missiles. The best defense against Russian/Chinese accidental launches is assistance to these countries in improving their launch control systems.

  18. Defense of a space elevator

    SciTech Connect

    Laubscher, B. E.

    2004-01-01

    The Space Elevator (SE) represents a major paradigm shift in space access. If the SE's promise of low-cost access is to be realized, everything becomes economically more feasible to accomplish in space. In this paper we describe a defensive system of the SE. The primary scenario adopted for this analysis is the SE based on a floating platform in the ocean along the equator. A second possible scenario is the SE stationed on land (island or continent) on or near the equator. The SE will capture the imaginations of people around the world. It will become a symbol of power, capability, wealth and prestige for the country that builds it. As such, it will become a prime terrorist target. Moreover, the tremendous economic leverage afforded by the SE might motivate rogue nations to plot its destruction. Therefore, it is necessary to consider the requirements for defense of the SE. For the purposes of this paper it is assumed that the SE is to be deployed by the United States or one of its companies, and the resources of the US are available for its defense.

  19. [Multiplication of Brucella abortus and production of nitric oxide in two macrophage cell lines of different origin].

    PubMed

    Serafino, J; Conde, S; Zabal, O; Samartino, L

    2007-01-01

    Brucella abortus is a bacterium which causes abortions and infertility in cattle and undulant fever in humans. It multiplies intracellularly, evading the mechanisms of cellular death. Nitric oxide (NO) is important in the regulation of the immune response. In the present work, we studied the ability of three B. abortus strains to survive intracellularly in two macrophage cell lines. The bacterial multiplication in both cell lines was determined at two different times in UFC/ ml units. Moreover the inoculated cells were also observed under light-field and fluorescence microscopy stained with Giemsa and acridine orange, respectively. The stain of both cellular lines showed similar results with respect to the UFC/ml determination. The presence of B. abortus was confirmed by electronic microscopy. In both macrophage cell lines inoculated with the rough strain RB51, the multiplication diminished and the level of NO was higher, compared with cells inoculated with smooth strains (S19 and 2308). These results suggest that the absence of O-chain of LPS probably affects the intracellular growth of B. abortus. PMID:18390151

  20. Candida albicans killing by RAW 264.7 mouse macrophage cells: effects of Candida genotype, infection ratios, and gamma interferon treatment.

    PubMed

    Marcil, A; Harcus, D; Thomas, D Y; Whiteway, M

    2002-11-01

    Phagocytic cells such as neutrophils and macrophages are potential components of the immune defense that protects mammals against Candida albicans infection. We have tested the interaction between the mouse macrophage cell line RAW 264.7 and a variety of mutant strains of C. albicans. We used an end point dilution assay to monitor the killing of C. albicans at low multiplicities of infection (MOIs). Several mutants that show reduced virulence in mouse systemic-infection models show reduced colony formation in the presence of macrophage cells. To permit analysis of the macrophage-Candida interaction at higher MOIs, we introduced a luciferase reporter gene into wild-type and mutant Candida cells and used loss of the luminescence signal to quantify proliferation. This assay gave results similar to those for the end point dilution assay. Activation of the macrophages with mouse gamma interferon did not enhance anti-Candida activity. Continued coculture of the Candida and macrophage cells eventually led to death of the macrophages, but for the RAW 264.7 cell line this was not due to apoptotic pathways involving caspase-8 or -9 activation. In general Candida cells defective in the formation of hyphae were both less virulent in animal models and more sensitive to macrophage engulfment and growth inhibition. However the nonvirulent, hypha-defective cla4 mutant line was considerably more resistant to macrophage-mediated inhibition than the wild-type strain. Thus although mutants sensitive to engulfment are typically less virulent in systemic-infection models, sensitivity to phagocytic macrophage cells is not the unique determinant of C. albicans virulence. PMID:12379711

  1. Toll-Like Receptor 9 Modulates Macrophage Antifungal Effector Function during Innate Recognition of Candida albicans and Saccharomyces cerevisiae▿†

    PubMed Central

    Kasperkovitz, Pia V.; Khan, Nida S.; Tam, Jenny M.; Mansour, Michael K.; Davids, Peter J.; Vyas, Jatin M.

    2011-01-01

    Phagocytic responses are critical for effective host defense against opportunistic fungal pathogens. Macrophages sample the phagosomal content and orchestrate the innate immune response. Toll-like receptor 9 (TLR9) recognizes unmethylated CpG DNA and is activated by fungal DNA. Here we demonstrate that specific triggering of TLR9 recruitment to the macrophage phagosomal membrane is a conserved feature of fungi of distinct phylogenetic origins, including Candida albicans, Saccharomyces cerevisiae, Malassezia furfur, and Cryptococcus neoformans. The capacity to trigger phagosomal TLR9 recruitment was not affected by a loss of fungal viability or cell wall integrity. TLR9 deficiency has been linked to increased resistance to murine candidiasis and to restriction of fungal growth in vivo. Macrophages lacking TLR9 demonstrate a comparable capacity for phagocytosis and normal phagosomal maturation compared to wild-type macrophages. We now show that TLR9 deficiency increases macrophage tumor necrosis factor alpha (TNF-α) production in response to C. albicans and S. cerevisiae, independent of yeast viability. The increase in TNF-α production was reversible by functional complementation of the TLR9 gene, confirming that TLR9 was responsible for negative modulation of the cytokine response. Consistently, TLR9 deficiency enhanced the macrophage effector response by increasing macrophage nitric oxide production. Moreover, microbicidal activity against C. albicans and S. cerevisiae was more efficient in TLR9 knockout (TLR9KO) macrophages than in wild-type macrophages. In conclusion, our data demonstrate that TLR9 is compartmentalized selectively to fungal phagosomes and negatively modulates macrophage antifungal effector functions. Our data support a model in which orchestration of antifungal innate immunity involves a complex interplay of fungal ligand combinations, host cell machinery rearrangements, and TLR cooperation and antagonism. PMID:21947771

  2. Radiological Defense. Planning and Operations Guide. Revised.

    ERIC Educational Resources Information Center

    Office of Civil Defense (DOD), Washington, DC.

    This guide is a reprint of published and draft materials from the Federal Civil Defense Guide. This guide is intended to assist the student in planning, developing, implementing and operating a local, county, or state radiological defense (RADEF) system. The state and local radiological defense program objectives are to create an effective and…

  3. 22 CFR 120.6 - Defense article.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Defense article. 120.6 Section 120.6 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.6 Defense article. Defense article means any item or technical data designated in § 121.1 of this...

  4. 22 CFR 120.6 - Defense article.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Defense article. 120.6 Section 120.6 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.6 Defense article. Defense article means any item or technical data designated in § 121.1 of this...

  5. 22 CFR 120.6 - Defense article.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Defense article. 120.6 Section 120.6 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.6 Defense article. Defense article means any item or technical data designated in § 121.1 of this...

  6. 22 CFR 120.9 - Defense service.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Defense service. 120.9 Section 120.9 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.9 Defense service. (a) Defense service means: (1) The furnishing of assistance (including training)...

  7. 22 CFR 120.9 - Defense service.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Defense service. 120.9 Section 120.9 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.9 Defense service. (a) Defense service means: (1) The furnishing of assistance (including training)...

  8. 22 CFR 120.9 - Defense service.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Defense service. 120.9 Section 120.9 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.9 Defense service. (a) Defense service means: (1) The furnishing of assistance (including training)...

  9. 22 CFR 120.9 - Defense service.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Defense service. 120.9 Section 120.9 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.9 Defense service. (a) Defense service means: (1) The furnishing of assistance (including training)...

  10. 22 CFR 120.9 - Defense service.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Defense service. 120.9 Section 120.9 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.9 Defense service. (a) Defense service means: (1) The furnishing of assistance (including training)...

  11. 75 FR 32416 - Defense Science Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-08

    ... of the Secretary Defense Science Board AGENCY: Department of Defense (DoD). ACTION: Notice of advisory committee meeting. SUMMARY: The Defense Science Board Task Force on the Survivability of DoD... Science Board Threat Reduction Advisory Committee (TRAC) Task Force findings, recommendations and...

  12. 22 CFR 120.6 - Defense article.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Defense article. 120.6 Section 120.6 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.6 Defense article. Defense article means any item or technical data designated in § 121.1 of this...

  13. Teaching Gibb's Taxonomy of Defensiveness through Performance

    ERIC Educational Resources Information Center

    Thomson, Deborah M.

    2008-01-01

    The topic of defensiveness resonates with students, who are generally eager to learn how to prevent it. Gibb's taxonomy of defensive/supportive behaviors is widely published and used today. According to Gibb, defensiveness occurs when a communicator puts substantial effort into defending him/herself from a perceived communicative threat. This…

  14. 22 CFR 120.6 - Defense article.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Defense article. 120.6 Section 120.6 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.6 Defense article. Defense article means any item or technical data designated in § 121.1 of this...

  15. Guardians of the Gut – Murine Intestinal Macrophages and Dendritic Cells

    PubMed Central

    Gross, Mor; Salame, Tomer-Meir; Jung, Steffen

    2015-01-01

    Intestinal mononuclear phagocytes find themselves in a unique environment, most prominently characterized by its constant exposure to commensal microbiota and food antigens. This anatomic setting has resulted in a number of specializations of the intestinal mononuclear phagocyte compartment that collectively contribute the unique steady state immune landscape of the healthy gut, including homeostatic innate lymphoid cells, B, and T cell compartments. As in other organs, macrophages and dendritic cells (DCs) orchestrate in addition the immune defense against pathogens, both in lymph nodes and mucosa-associated lymphoid tissue. Here, we will discuss origins and functions of intestinal DCs and macrophages and their respective subsets, focusing largely on the mouse and cells residing in the lamina propria. PMID:26082775

  16. An Arginine Deprivation Response Pathway Is Induced in Leishmania during Macrophage Invasion

    PubMed Central

    Strasser, Rona; Zeituni-Molad, Michal; Bendelak, Keren; Rentsch, Doris; Ephros, Moshe; Wiese, Martin; Jardim, Armando; Myler, Peter J.; Zilberstein, Dan

    2016-01-01

    Amino acid sensing is an intracellular function that supports nutrient homeostasis, largely through controlled release of amino acids from lysosomal pools. The intracellular pathogen Leishmania resides and proliferates within human macrophage phagolysosomes. Here we describe a new pathway in Leishmania that specifically senses the extracellular levels of arginine, an amino acid that is essential for the parasite. During infection, the macrophage arginine pool is depleted due to its use to produce metabolites (NO and polyamines) that constitute part of the host defense response and its suppression, respectively. We found that parasites respond to this shortage of arginine by up-regulating expression and activity of the Leishmania arginine transporter (LdAAP3), as well as several other transporters. Our analysis indicates the parasite monitors arginine levels in the environment rather than the intracellular pools. Phosphoproteomics and genetic analysis indicates that the arginine-deprivation response is mediated through a mitogen-activated protein kinase-2-dependent signaling cascade. PMID:27043018

  17. An Arginine Deprivation Response Pathway Is Induced in Leishmania during Macrophage Invasion.

    PubMed

    Goldman-Pinkovich, Adele; Balno, Caitlin; Strasser, Rona; Zeituni-Molad, Michal; Bendelak, Keren; Rentsch, Doris; Ephros, Moshe; Wiese, Martin; Jardim, Armando; Myler, Peter J; Zilberstein, Dan

    2016-04-01

    Amino acid sensing is an intracellular function that supports nutrient homeostasis, largely through controlled release of amino acids from lysosomal pools. The intracellular pathogen Leishmania resides and proliferates within human macrophage phagolysosomes. Here we describe a new pathway in Leishmania that specifically senses the extracellular levels of arginine, an amino acid that is essential for the parasite. During infection, the macrophage arginine pool is depleted due to its use to produce metabolites (NO and polyamines) that constitute part of the host defense response and its suppression, respectively. We found that parasites respond to this shortage of arginine by up-regulating expression and activity of the Leishmania arginine transporter (LdAAP3), as well as several other transporters. Our analysis indicates the parasite monitors arginine levels in the environment rather than the intracellular pools. Phosphoproteomics and genetic analysis indicates that the arginine-deprivation response is mediated through a mitogen-activated protein kinase-2-dependent signaling cascade. PMID:27043018

  18. Dectin-1–Dependent LC3 Recruitment to Phagosomes Enhances Fungicidal Activity in Macrophages

    PubMed Central

    Tam, Jenny M.; Mansour, Michael K.; Khan, Nida S.; Seward, Michael; Puranam, Sravanthi; Tanne, Antoine; Sokolovska, Anna; Becker, Christine E.; Acharya, Mridu; Baird, Michelle A.; Choi, Augustine M. K.; Davidson, Michael W.; Segal, Brahm H.; Lacy-Hulbert, Adam; Stuart, Lynda M.; Xavier, Ramnik J.; Vyas, Jatin M.

    2014-01-01

    Autophagy has been postulated to play role in mammalian host defense against fungal pathogens, although the molecular details remain unclear. Here, we show that primary macrophages deficient in the autophagic factor LC3 demonstrate diminished fungicidal activity but increased cytokine production in response to Candida albicans stimulation. LC3 recruitment to fungal phagosomes requires activation of the fungal pattern receptor dectin-1. LC3 recruitment to the phagosome also requires Syk signaling but is independent of all activity by Toll-like receptors and does not require the presence of the adaptor protein Card9. We further demonstrate that reactive oxygen species generation by NADPH oxidase is required for LC3 recruitment to the fungal phagosome. These observations directly link LC3 to the inflammatory pathway against C. albicans in macrophages. PMID:24842831

  19. Dectin-1-dependent LC3 recruitment to phagosomes enhances fungicidal activity in macrophages.

    PubMed

    Tam, Jenny M; Mansour, Michael K; Khan, Nida S; Seward, Michael; Puranam, Sravanthi; Tanne, Antoine; Sokolovska, Anna; Becker, Christine E; Acharya, Mridu; Baird, Michelle A; Choi, Augustine M K; Davidson, Michael W; Segal, Brahm H; Lacy-Hulbert, Adam; Stuart, Lynda M; Xavier, Ramnik J; Vyas, Jatin M

    2014-12-01

    Autophagy has been postulated to play role in mammalian host defense against fungal pathogens, although the molecular details remain unclear. Here, we show that primary macrophages deficient in the autophagic factor LC3 demonstrate diminished fungicidal activity but increased cytokine production in response to Candida albicans stimulation. LC3 recruitment to fungal phagosomes requires activation of the fungal pattern receptor dectin-1. LC3 recruitment to the phagosome also requires Syk signaling but is independent of all activity by Toll-like receptors and does not require the presence of the adaptor protein Card9. We further demonstrate that reactive oxygen species generation by NADPH oxidase is required for LC3 recruitment to the fungal phagosome. These observations directly link LC3 to the inflammatory pathway against C. albicans in macrophages. PMID:24842831

  20. Elucidation of monocyte/macrophage dynamics and function by intravital imaging

    PubMed Central

    Rua, Rejane; McGavern, Dorian B.

    2015-01-01

    Monocytes and macrophages are a diverse population of innate immune cells that play a critical role in homeostasis and inflammation. These cells are surveillant by nature and closely monitor the vasculature and surrounding tissue during states of health and disease. Given their abundance and strategic positioning throughout the body, myeloid cells are among the first responders to any inflammatory challenge and are active participants in most immune-mediated diseases. Recent studies have shed new light on myeloid cell dynamics and function by use of an imaging technique referred to as intravital microscopy (IVM). This powerful approach allows researchers to gain real-time insights into monocytes and macrophages performing homeostatic and inflammatory tasks in living tissues. In this review, we will present a contemporary synopsis of how intravital microscopy has revolutionized our understanding of myeloid cell contributions to vascular maintenance, microbial defense, autoimmunity, tumorigenesis, and acute/chronic inflammatory diseases. PMID:26162402

  1. Electrophysiological characterization of the first Tityus serrulatus alpha-like toxin, Ts5: Evidence of a pro-inflammatory toxin on macrophages.

    PubMed

    Pucca, Manuela B; Peigneur, Steve; Cologna, Camila T; Cerni, Felipe A; Zoccal, Karina F; Bordon, Karla de C F; Faccioli, Lucia H; Tytgat, Jan; Arantes, Eliane C

    2015-08-01

    Tityus serrulatus (Ts) venom is composed of mainly neurotoxins specific for voltage-gated K(+) and Na(+) channels, which are expressed in many cells such as macrophages. Macrophages are the first line of defense invasion and they participate in the inflammatory response of Ts envenoming. However, little is known about the effect of Ts toxins on macrophage activation. This study investigated the effect of Ts5 toxin on different sodium channels as well as its role on the macrophage immunomodulation. The electrophysiological assays showed that Ts5 inhibits the rapid inactivation of the mammalian sodium channels Nav1.2, Nav1.3, Nav1.4, Nav1.5, Nav1.6 and Nav1.7. Interestingly, Ts5 also inhibits the inactivation of the insect Drosophila melanogaster sodium channel (DmNav1), and it is therefore classified as the first Ts α-like toxin. The immunological experiments on macrophages reveal that Ts5 is a pro-inflammatory toxin inducing the cytokine production of tumor necrosis factor (TNF)-α and interleukin (IL)-6. On the basis of recent literature, our study also stresses a possible mechanism responsible for venom-associated molecular patterns (VAMPs) internalization and macrophage activation and moreover we suggest two main pathways of VAMPs signaling: direct and indirect. This work provides useful insights for a better understanding of the involvement of VAMPs in macrophage modulation. PMID:25906692

  2. Effect of aqueous extract of Tinospora cordifolia on functions of peritoneal macrophages isolated from CCl4 intoxicated male albino mice

    PubMed Central

    2011-01-01

    cordifolia at a dose of 150 mg/kg body weight. Conclusion From our findings it can be suggested that, polar fractions of Tinospora cordifolia stem parts contain major bioactive compounds, which directly act on peritoneal macrophages and have been found to boost the non-specific host defenses of the immune system. However, the molecular mechanism of this activity of Tinospora cordifolia on immune functions needs to be elucidated. PMID:22035196

  3. 22 CFR 120.2 - Designation of defense articles and defense services.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Designation of defense articles and defense services. 120.2 Section 120.2 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.2 Designation of defense articles and defense services. The...

  4. 75 FR 52732 - Renewal of Department of Defense Federal Advisory Committee; Missile Defense Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-27

    ... Secretary of Defense for Acquisition, Technology & Logistics and the Director, Missile Defense Agency... Advisory Committee AGENCY: Department of Defense (DoD). ACTION: Renewal of Federal Advisory Committee... System. The Under Secretary of Defense for Acquisition, Technology and Logistics or designee may act...

  5. 22 CFR 120.2 - Designation of defense articles and defense services.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Designation of defense articles and defense services. 120.2 Section 120.2 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.2 Designation of defense articles and defense services. The...

  6. 22 CFR 120.2 - Designation of defense articles and defense services.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Designation of defense articles and defense services. 120.2 Section 120.2 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.2 Designation of defense articles and defense services. The...

  7. 76 FR 72391 - Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-23

    ... (DLA) published a Notice of Availability (NOA) in the Federal Register (76 FR 28757) announcing the... of the Secretary Defense Logistics Agency Revised Regulation 1000.22, Environmental Considerations in Defense Logistics Agency Actions AGENCY: Defense Logistics Agency, Department of Defense. ACTION:...

  8. 75 FR 13093 - Renewal of Department of Defense Federal Advisory Committee; Defense Acquisition University Board...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Office of the Secretary Renewal of Department of Defense Federal Advisory Committee; Defense Acquisition University Board of Visitors AGENCY: Department of Defense (DoD). ACTION: Renewal of Federal...

  9. 78 FR 78163 - Eligibility of the Gulf Cooperation Council To Receive Defense Articles and Defense Services...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ..., Washington, December 16, 2013. [FR Doc. 2013-30984 Filed 12-23-13; 11:15 am] Billing code 4710-10 ... Cooperation Council To Receive Defense Articles and Defense Services Under the Foreign Assistance Act of 1961... that the furnishing of defense articles and defense services to the Gulf Cooperation Council...

  10. 22 CFR 120.2 - Designation of defense articles and defense services.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Designation of defense articles and defense services. 120.2 Section 120.2 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS PURPOSE AND DEFINITIONS § 120.2 Designation of defense articles and defense services. The...

  11. Lipid Droplet Formation, Their Localization and Dynamics during Leishmania major Macrophage Infection.

    PubMed

    Rabhi, Sameh; Rabhi, Imen; Trentin, Bernadette; Piquemal, David; Regnault, Béatrice; Goyard, Sophie; Lang, Thierry; Descoteaux, Albert; Enninga, Jost; Guizani-Tabbane, Lamia

    2016-01-01

    Leishmania, the causative agent of vector-borne diseases, known as leishmaniases, is an obligate intracellular parasite within mammalian hosts. The outcome of infection depends largely on the activation status of macrophages, the first line of mammalian defense and the major target cells for parasite replication. Understanding the strategies developed by the parasite to circumvent macrophage defense mechanisms and to survive within those cells help defining novel therapeutic approaches for leishmaniasis. We previously showed the formation of lipid droplets (LDs) in L. major infected macrophages. Here, we provide novel insights on the origin of the formed LDs by determining their cellular distribution and to what extent these high-energy sources are directed to the proximity of Leishmania parasites. We show that the ability of L. major to trigger macrophage LD accumulation is independent of parasite viability and uptake and can also be observed in non-infected cells through paracrine stimuli suggesting that LD formation is from cellular origin. The accumulation of LDs is demonstrated using confocal microscopy and live-cell imagin in parasite-free cytoplasmic region of the host cell, but also promptly recruited to the proximity of Leishmania parasites. Indeed LDs are observed inside parasitophorous vacuole and in parasite cytoplasm suggesting that Leishmania parasites besides producing their own LDs, may take advantage of these high energy sources. Otherwise, these LDs may help cells defending against parasitic infection. These metabolic changes, rising as common features during the last years, occur in host cells infected by a large number of pathogens and seem to play an important role in pathogenesis. Understanding how Leishmania parasites and different pathogens exploit this LD accumulation will help us define the common mechanism used by these different pathogens to manipulate and/or take advantage of this high-energy source. PMID:26871576

  12. Lipid Droplet Formation, Their Localization and Dynamics during Leishmania major Macrophage Infection

    PubMed Central

    Rabhi, Sameh; Rabhi, Imen; Trentin, Bernadette; Piquemal, David; Regnault, Béatrice; Goyard, Sophie; Lang, Thierry; Descoteaux, Albert; Enninga, Jost; Guizani-Tabbane, Lamia

    2016-01-01

    Leishmania, the causative agent of vector-borne diseases, known as leishmaniases, is an obligate intracellular parasite within mammalian hosts. The outcome of infection depends largely on the activation status of macrophages, the first line of mammalian defense and the major target cells for parasite replication. Understanding the strategies developed by the parasite to circumvent macrophage defense mechanisms and to survive within those cells help defining novel therapeutic approaches for leishmaniasis. We previously showed the formation of lipid droplets (LDs) in L. major infected macrophages. Here, we provide novel insights on the origin of the formed LDs by determining their cellular distribution and to what extent these high-energy sources are directed to the proximity of Leishmania parasites. We show that the ability of L. major to trigger macrophage LD accumulation is independent of parasite viability and uptake and can also be observed in non-infected cells through paracrine stimuli suggesting that LD formation is from cellular origin. The accumulation of LDs is demonstrated using confocal microscopy and live-cell imagin in parasite-free cytoplasmic region of the host cell, but also promptly recruited to the proximity of Leishmania parasites. Indeed LDs are observed inside parasitophorous vacuole and in parasite cytoplasm suggesting that Leishmania parasites besides producing their own LDs, may take advantage of these high energy sources. Otherwise, these LDs may help cells defending against parasitic infection. These metabolic changes, rising as common features during the last years, occur in host cells infected by a large number of pathogens and seem to play an important role in pathogenesis. Understanding how Leishmania parasites and different pathogens exploit this LD accumulation will help us define the common mechanism used by these different pathogens to manipulate and/or take advantage of this high-energy source. PMID:26871576

  13. NMAAP1 Expressed in BCG-Activated Macrophage Promotes M1 Macrophage Polarization

    PubMed Central

    Liu, Qihui; Tian, Yuan; Zhao, Xiangfeng; Jing, Haifeng; Xie, Qi; Li, Peng; Li, Dong; Yan, Dongmei; Zhu, Xun

    2015-01-01

    Macrophages are divided into two subpopulations: classically activated macrophages (M1) and alternatively activated macrophages (M2). BCG (Bacilli Calmette-Guérin) activates disabled naïve macrophages to M1 macrophages, which act as inflammatory, microbicidal and tumoricidal cells through cell-cell contact and/or the release of soluble factors. Various transcription factors and signaling pathways are involved in the regulation of macrophage activation and polarization. We discovered that BCG-activated macrophages (BAM) expressed a new molecule, and we named it Novel Macrophage Activated Associated Protein 1 (NMAAP1). The current study found that the overexpression of NMAAP1 in macrophages results in M1 polarization with increased expression levels of M1 genes, such as inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), Interleukin 6 (IL-6), Interleukin 12 (IL-12), Monocyte chemoattractant protein-1 (MCP-1) and Interleukin-1 beta (IL-1β), and decreased expression of some M2 genes, such as Kruppel-like factor 4 (KLF4) and suppressor of cytokine signaling 1 (SOCS1), but not other M2 genes, including arginase-1 (Arg-1), Interleukin (IL-10), transforming growth factor beta (TGF-β) and found in inflammatory zone 1 (Fizz1). Moreover, NMAAP1 overexpression in the RAW264.7 cell line increased cytotoxicity against MCA207 tumor cells, which depends on increased inflammatory cytokines rather than cell-cell contact. NMAAP1 also substantially enhanced the phagocytic ability of macrophages, which implies that NMAAP1 promoted macrophage adhesive and clearance activities. Our results indicate that NMAAP1 is an essential molecule that modulates macrophages phenotype and plays an important role in macrophage tumoricidal functions. PMID:26429502

  14. Susceptibility of bone marrow-derived macrophages to influenza virus infection is dependent on macrophage phenotype

    PubMed Central

    Campbell, Gillian M.; Nicol, Marlynne Q.; Dransfield, Ian; Shaw, Darren J.; Nash, Anthony A.

    2015-01-01

    The role of the macrophage in influenza virus infection is complex. Macrophages are critical for resolution of influenza virus infections but implicated in morbidity and mortality in severe infections. They can be infected with influenza virus and consequently macrophage infection is likely to have an impact on the host immune response. Macrophages display a range of functional phenotypes, from the prototypical pro-inflammatory classically activated cell to alternatively activated anti-inflammatory macrophages involved in immune regulation and wound healing. We were interested in how macrophages of different phenotype respond to influenza virus infection and therefore studied the infection of bone marrow-derived macrophages (BMDMs) of classical and alternative phenotype in vitro. Our results show that alternatively activated macrophages are more readily infected and killed by the virus than classically activated. Classically activated BMDMs express the pro-inflammatory markers inducible nitric oxide synthase (iNOS) and TNF-α, and TNF-α expression was further upregulated following infection. Alternatively activated macrophages express Arginase-1 and CD206; however, following infection, expression of these markers was downregulated whilst expression of iNOS and TNF-α was upregulated. Thus, infection can override the anti-inflammatory state of alternatively activated macrophages. Importantly, however, this results in lower levels of pro-inflammatory markers than those produced by classically activated cells. Our results showed that macrophage phenotype affects the inflammatory macrophage response following infection, and indicated that modulating the macrophage phenotype may provide a route to develop novel strategies to prevent and treat influenza virus infection. PMID:26297234

  15. Susceptibility of bone marrow-derived macrophages to influenza virus infection is dependent on macrophage phenotype.

    PubMed

    Campbell, Gillian M; Nicol, Marlynne Q; Dransfield, Ian; Shaw, Darren J; Nash, Anthony A; Dutia, Bernadette M

    2015-10-01

    The role of the macrophage in influenza virus infection is complex. Macrophages are critical for resolution of influenza virus infections but implicated in morbidity and mortality in severe infections. They can be infected with influenza virus and consequently macrophage infection is likely to have an impact on the host immune response. Macrophages display a range of functional phenotypes, from the prototypical pro-inflammatory classically activated cell to alternatively activated anti-inflammatory macrophages involved in immune regulation and wound healing. We were interested in how macrophages of different phenotype respond to influenza virus infection and therefore studied the infection of bone marrow-derived macrophages (BMDMs) of classical and alternative phenotype in vitro. Our results show that alternatively activated macrophages are more readily infected and killed by the virus than classically activated. Classically activated BMDMs express the pro-inflammatory markers inducible nitric oxide synthase (iNOS) and TNF-α, and TNF-α expression was further upregulated following infection. Alternatively activated macrophages express Arginase-1 and CD206; however, following infection, expression of these markers was downregulated whilst expression of iNOS and TNF-α was upregulated. Thus, infection can override the anti-inflammatory state of alternatively activated macrophages. Importantly, however, this results in lower levels of pro-inflammatory markers than those produced by classically activated cells. Our results showed that macrophage phenotype affects the inflammatory macrophage response following infection, and indicated that modulating the macrophage phenotype may provide a route to develop novel strategies to prevent and treat influenza virus infection. PMID:26297234

  16. Parasitophorous vacuoles of Leishmania amazonensis-infected macrophages maintain an acidic pH.

    PubMed Central

    Antoine, J C; Prina, E; Jouanne, C; Bongrand, P

    1990-01-01

    Leishmania amastigotes are intracellular protozoan parasites of mononuclear phagocytes which reside within parasitophorous vacuoles of phagolysosomal origin. The pH of these compartments was studied with the aim of elucidating strategies used by these microorganisms to evade the microbicidal mechanisms of their host cells. For this purpose, rat bone marrow-derived macrophages were infected with L. amazonensis amastigotes. Intracellular acidic compartments were localized by using the weak base 3-(2,4-dinitroanilino)-3'-amino-N-methyldipropylamine as a probe. This indicator, which can be detected by light microscopy by using immunocytochemical methods, mainly accumulated in perinuclear lysosomes of uninfected cells, whereas in infected cells, it was essentially localized in parasitophorous vacuoles, which thus appeared acidified. Phagolysosomal pH was estimated quantitatively in living cells loaded with the pH-sensitive endocytic tracer fluoresceinated dextran. After a 15- to 20-h exposure, the tracer was mainly detected in perinuclear lysosomes and parasitophorous vacuoles of uninfected and infected macrophages, respectively. Fluorescence intensities were determined from digitized video images of single cells after processing and automatic subtraction of background. We found statistically different mean pH values of 5.17 to 5.48 for lysosomes and 4.74 to 5.26 for parasitophorous vacuoles. As for lysosomes of monensin-treated cells, the pH gradient of parasitophorous vacuoles collapsed after monensin was added. This very likely indicates that these vacuoles maintain an acidic internal pH by an active process. These results show that L. amazonensis amastigotes are acidophilic and opportunistic organisms and suggest that these intracellular parasites have evolved means for survival under these harsh conditions and have acquired plasma membrane components compatible with the environment. Images PMID:1689700

  17. Ontogeny of Tissue-Resident Macrophages

    PubMed Central

    Hoeffel, Guillaume; Ginhoux, Florent

    2015-01-01

    The origin of tissue-resident macrophages, crucial for homeostasis and immunity, has remained controversial until recently. Originally described as part of the mononuclear phagocyte system, macrophages were long thought to derive solely from adult blood circulating monocytes. However, accumulating evidence now shows that certain macrophage populations are in fact independent from monocyte and even from adult bone marrow hematopoiesis. These tissue-resident macrophages derive from sequential seeding of tissues by two precursors during embryonic development. Primitive macrophages generated in the yolk sac (YS) from early erythro-myeloid progenitors (EMPs), independently of the transcription factor c-Myb and bypassing monocytic intermediates, first give rise to microglia. Later, fetal monocytes, generated from c-Myb+ EMPs that initially seed the fetal liver (FL), then give rise to the majority of other adult macrophages. Thus, hematopoietic stem cell-independent embryonic precursors transiently present in the YS and the FL give rise to long-lasting self-renewing macrophage populations. PMID:26441990

  18. Developmental origin of lung macrophage diversity.

    PubMed

    Tan, Serena Y S; Krasnow, Mark A

    2016-04-15

    Macrophages are specialized phagocytic cells, present in all tissues, which engulf and digest pathogens, infected and dying cells, and debris, and can recruit and regulate other immune cells and the inflammatory response and aid in tissue repair. Macrophage subpopulations play distinct roles in these processes and in disease, and are typically recognized by differences in marker expression, immune function, or tissue of residency. Although macrophage subpopulations in the brain have been found to have distinct developmental origins, the extent to which development contributes to macrophage diversity between tissues and within tissues is not well understood. Here, we investigate the development and maintenance of mouse lung macrophages by marker expression patterns, genetic lineage tracing and parabiosis. We show that macrophages populate the lung in three developmental waves, each giving rise to a distinct lineage. These lineages express different markers, reside in different locations, renew in different ways, and show little or no interconversion. Thus, development contributes significantly to lung macrophage diversity and targets each lineage to a different anatomical domain. PMID:26952982

  19. Macrophage epoxygenase determines a profibrotic transcriptome signature.

    PubMed

    Behmoaras, Jacques; Diaz, Ana Garcia; Venda, Lara; Ko, Jeong-Hun; Srivastava, Prashant; Montoya, Alex; Faull, Peter; Webster, Zoe; Moyon, Ben; Pusey, Charles D; Abraham, David J; Petretto, Enrico; Cook, Terence H; Aitman, Timothy J

    2015-05-15

    Epoxygenases belong to the cytochrome P450 family. They generate epoxyeicosatrienoic acids, which are known to have anti-inflammatory effects, but little is known about their role in macrophage function. By high-throughput sequencing of RNA in primary macrophages derived from rodents and humans, we establish the relative expression of epoxygenases in these cells. Zinc-finger nuclease-mediated targeted gene deletion of the major rat macrophage epoxygenase Cyp2j4 (ortholog of human CYP2J2) resulted in reduced epoxyeicosatrienoic acid synthesis. Cyp2j4(-/-) macrophages have relatively increased peroxisome proliferator-activated receptor-γ levels and show a profibrotic transcriptome, displaying overexpression of a specific subset of genes (260 transcripts) primarily involved in extracellular matrix, with fibronectin being the most abundantly expressed transcript. Fibronectin expression is under the control of epoxygenase activity in human and rat primary macrophages. In keeping with the in vitro findings, Cyp2j4(-/-) rats show upregulation of type I collagen following unilateral ureter obstruction of the kidney, and quantitative proteomics analysis (liquid chromatography-tandem mass spectrometry) showed increased renal type I collagen and fibronectin protein abundance resulting from experimentally induced crescentic glomerulonephritis in these rats. Taken together, these results identify the rat epoxygenase Cyp2j4 as a determinant of a profibrotic macrophage transcriptome that could have implications in various inflammatory conditions, depending on macrophage function. PMID:25840911

  20. Lung Macrophage Diversity and Asthma.

    PubMed

    Lumeng, Carey N

    2016-03-01

    Macrophages (MPs) are one of the most prominent leukocyte populations in the lung and, in many ways, a forgotten player in asthma pathogenesis. Diverse functions in asthma initiation and maintenance in chronic disease have been demonstrated, which has led to confusion as to if pulmonary MPs are agents of good or evil in asthma. Much of this is due to the wide diversity of MP populations in the lung, many of which are inaccessible experimentally in most clinical studies. This review frames lung MP biology in the context of location, phenotype, function, and response phase in asthma pathogenesis. It also assesses new findings regarding MP diversity that have challenged old dogmas and generates new ways to understand how MPs function. PMID:27027949

  1. IDENTIFICATION AND EXPRESSION OF MACROPHAGE MIGRATION INHIBITORY FACTOR IN SARCOPTES SCABIEI

    PubMed Central

    COTE’, N.M.; JAWORSKI, D.C.; WASALA, N.B.; MORGAN, M.S.; ARLIAN, L. G.

    2013-01-01

    Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory cytokine produced by many mammalian tissues including skin. It is also found in many invertebrate parasites of mammals including ticks and may function to aid the parasite to evade the innate and adaptive immune responses in the host. In this study, the cDNA for a MIF gene was sequenced from Sarcoptes scabiei, the scabies mite, using RT-PCR and RACE molecular techniques. The resulting nucleotide sequence had a length of 405 base pairs and the putative amino acid sequences for the mite and tick (Dermacentor variabilis) proteins were identical. The initial steps for the project resulted in the production of expressed scabies mite cDNAs. A real time (qPCR) assay was performed with MIF from scabies mites and various tick species. Results show that mRNA encoding MIF homologues was three times more abundant in the mite samples when compared to RNA prepared from D. variabilis salivary glands and 1.3 times more abundant when compared with RNA prepared from D. variabilis midgut. PMID:23831036

  2. Macrophage subsets and microglia in multiple sclerosis.

    PubMed

    Bogie, Jeroen F J; Stinissen, Piet; Hendriks, Jerome J A

    2014-08-01

    Along with microglia and monocyte-derived macrophages, macrophages in the perivascular space, choroid plexus, and meninges are the principal effector cells in neuroinflammatory and neurodegenerative disorders. These phagocytes are highly heterogeneous cells displaying spatial- and temporal-dependent identities in the healthy, injured, and inflamed CNS. In the last decade, researchers have debated on whether phagocytes subtypes and phenotypes are pathogenic or protective in CNS pathologies. In the context of this dichotomy, we summarize and discuss the current knowledge on the spatiotemporal physiology of macrophage subsets and microglia in the healthy and diseased CNS, and elaborate on factors regulating their behavior. In addition, the impact of macrophages present in lymphoid organs on CNS pathologies is defined. The prime focus of this review is on multiple sclerosis (MS), which is characterized by inflammation, demyelination, neurodegeneration, and CNS repair, and in which microglia and macrophages have been extensively scrutinized. On one hand, microglia and macrophages promote neuroinflammatory and neurodegenerative events in MS by releasing inflammatory mediators and stimulating leukocyte activity and infiltration into the CNS. On the other hand, microglia and macrophages assist in CNS repair through the production of neurotrophic factors and clearance of inhibitory myelin debris. Finally, we define how microglia and macrophage physiology can be harnessed for new therapeutics aimed at suppressing neuroinflammatory and cytodegenerative events, as well as promoting CNS repair. We conclude that microglia and macrophages are highly dynamic cells displaying disease stage and location-specific fates in neurological disorders. Changing the physiology of divergent phagocyte subsets at particular disease stages holds promise for future therapeutics for CNS pathologies. PMID:24952885

  3. [Adipose-derived stem cells promote the polarization from M1 macrophages to M2 macrophages].

    PubMed

    Yin, Xuehong; Pang, Chunyan; Bai, Li; Zhang, Ying; Geng, Lixia

    2016-03-01

    Objective To investigate the effects of adipose-derived stem cells (ADSCs) on M1/M2 macrophages and whether ADSCs are able to promote the polarization from M1 macrophages to M2 macrophages. Methods M1 macrophages were induced from J774.1 macrophages by 24-hour stimulation of lipopolysaccharide (LPS) and interferon γ (IFN-γ), and M2 macrophages were induced from J774.1 macrophages by interleukin 4 (IL-4) for another 24 hours. Then M1/M2 macrophages were separately cultured in the presence of ADSCs for 24 hours. The M1/M2 macrophages and their corresponding supernatants were collected for further analysis. The expressions of IL-6, tumor necrosis factor α (TNF-α), inducible nitric oxide synthase (iNOS), CC chemokine ligand 2 (CCL2), CD86, arginase 1 (Arg1), mannose receptors/CD206 (MR/CD206), IL-10, found in inflammatory zone 1 (FIZZ1), chitinase 3-like 3 (Ym-1) were detected by real-time PCR and ELISA. Results ADSCs significantly decreased the levels of IL-6, TNF-α, iNOS, CCL2 and CD86, and increased the levels of Arg1, CD206 and IL-10 in M1 macrophages. In the supernatant of M1 macrophages, the expressions of IL-6 and TNF-α were reduced, while those of CD206 were enhanced. In M2 macrophages, ADSCs resulted in down-regulation of IL-6, TNF-α, iNOS, CD86 and up-regulation of Arg1, CD206, FIZZ-1, Ym-1 and IL-10. In the supernatant of M2 macrophages, the expression levels of IL-6 and TNF-α were down-regulated and those of CD206 were up-regulated. Conclusion ADSCs can inhibit the gene expression of M1 macrophages and promote the gene expression of M2 macrophages, as well as mediate the polarization from M1 macrophages to M2 macrophages. PMID:26927552

  4. Regulation of IL-10 and IL-12 production and function in macrophages and dendritic cells

    PubMed Central

    Ma, Xiaojing; Yan, Wenjun; Zheng, Hua; Du, Qinglin; Zhang, Lixing; Ban, Yi; Li, Na; Wei, Fang

    2015-01-01

    Interleukin-10 and Interleukin-12 are produced primarily by pathogen-activated antigen-presenting cells, particularly macrophages and dendritic cells. IL-10 and IL-12 play very important immunoregulatory roles in host defense and immune homeostasis. Being anti- and pro-inflammatory in nature, respectively, their functions are antagonistically opposing. A comprehensive and in-depth understanding of their immunological properties and signaling mechanisms will help develop better clinical intervention strategies in therapy for a wide range of human disorders. Here, we provide an update on some emerging concepts, controversies, unanswered questions, and opinions regarding the immune signaling of IL-10 and IL-12. PMID:26918147

  5. ERK Signaling Is Essential for Macrophage Development.

    PubMed

    Richardson, Edward T; Shukla, Supriya; Nagy, Nancy; Boom, W Henry; Beck, Rose C; Zhou, Lan; Landreth, Gary E; Harding, Clifford V

    2015-01-01

    Macrophages depend on colony stimulating factor 1 (also known as M-CSF) for their growth and differentiation, but the requirements for intracellular signals that lead to macrophage differentiation and function remain unclear. M-CSF is known to activate ERK1 and ERK2, but the importance of this signaling pathway in macrophage development is unknown. In these studies, we characterized a novel model of Erk1(-/-) Erk2(flox/flox) Lyz2(Cre/Cre) mice in which the ERK2 isoform is deleted from macrophages in the background of global ERK1 deficiency. Cultures of M-CSF-stimulated bone marrow precursors from these mice yielded reduced numbers of macrophages. Whereas macrophages developing from M-CSF-stimulated bone marrow of Erk2(flox/flox) Lyz2(Cre/Cre) mice showed essentially complete loss of ERK2 expression, the reduced number of macrophages that develop from Erk1(-/-) Erk2(flox/flox) Lyz2(Cre/Cre) bone marrow show retention of ERK2 expression, indicating selective outgrowth of a small proportion of precursors in which Cre-mediated deletion failed to occur. The bone marrow of Erk1(-/-) Erk2(flox/flox) Lyz2(Cre/Cre) mice was enriched for CD11b+ myeloid cells, CD11b(hi) Gr-1(hi) neutrophils, Lin- c-Kit+ Sca-1+ hematopoietic stem cells, and Lin- c-Kit+ CD34+ CD16/32+ granulocyte-macrophage progenitors. Culture of bone marrow Lin- cells under myeloid-stimulating conditions yielded reduced numbers of monocytes. Collectively, these data indicate that the defect in production of macrophages is not due to a reduced number of progenitors, but rather due to reduced ability of progenitors to proliferate and produce macrophages in response to M-CSF-triggered ERK signaling. Macrophages from Erk1(-/-) Erk2(flox/flox) Lyz2(Cre/Cre) bone marrow showed reduced induction of M-CSF-regulated genes that depend on the ERK pathway for their expression. These data demonstrate that ERK1/ERK2 play a critical role in driving M-CSF-dependent proliferation of bone marrow progenitors for production of

  6. Effect of aflatoxins on rat peritoneal macrophages.

    PubMed Central

    Cusumano, V; Costa, G B; Seminara, S

    1990-01-01

    Phagocytosis, intracellular killing of Candida albicans, and superoxide production by rat peritoneal macrophages exposed to aflatoxins B1, B2, G1, G2, B2a, and M1 at several times and concentrations were analyzed to evaluate the intensity of a depressive effect for each mycotoxin. All aflatoxins used at very low concentrations had a depressive effect on the functions of macrophages. The biggest impairment of phagocytosis, intracellular killing, and spontaneous superoxide production was observed in macrophages exposed to aflatoxins B1 and M1. PMID:2176448

  7. Macrophages and Uveitis in Experimental Animal Models

    PubMed Central

    Mérida, Salvador; Palacios, Elena; Bosch-Morell, Francisco

    2015-01-01

    Resident and infiltrated macrophages play relevant roles in uveitis as effectors of innate immunity and inductors of acquired immunity. They are major effectors of tissue damage in uveitis and are also considered to be potent antigen-presenting cells. In the last few years, experimental animal models of uveitis have enabled us to enhance our understanding of the leading role of macrophages in eye inflammation processes, including macrophage polarization in experimental autoimmune uveoretinitis and the major role of Toll-like receptor 4 in endotoxin-induced uveitis. This improved knowledge should guide advantageous iterative research to establish mechanisms and possible therapeutic targets for human uveitis resolution. PMID:26078494

  8. Macrophage cell death upon intracellular bacterial infection

    PubMed Central

    Lai, Xin-He; Xu, Yunsheng; Chen, Xiao-Ming; Ren, Yi

    2015-01-01

    Macrophage-pathogen interaction is a complex process and the outcome of this tag-of-war for both sides is to live or die. Without attempting to be comprehensive, this review will discuss the complexity and significance of the interaction outcomes between macrophages and some facultative intracellular bacterial pathogens as exemplified by Francisella, Salmonella, Shigella and Yersinia. Upon bacterial infection, macrophages can die by a variety of ways, such as apoptosis, autophagic cell death, necrosis, necroptosis, oncosis, pyronecrosis, pyroptosis etc, which is the focus of this review. PMID:26690967

  9. Anoctamin 6 mediates effects essential for innate immunity downstream of P2X7 receptors in macrophages

    NASA Astrophysics Data System (ADS)

    Ousingsawat, Jiraporn; Wanitchakool, Podchanart; Kmit, Arthur; Romao, Ana M.; Jantarajit, Walailak; Schreiber, Rainer; Kunzelmann, Karl

    2015-02-01

    Purinergic P2X7 receptors (P2X7R) are fundamental to innate immune response. In macrophages, transient stimulation of P2X7R activates several transport mechanisms and induces the scrambling of phospholipids with subsequent membrane blebbing and apoptosis. These processes support phagocytosis and subsequent killing of phagocytosed bacteria. Here we demonstrate that the stimulation of P2X7 receptors activates anoctamin 6 (ANO6, TMEM16F), a protein that functions as Ca2+ dependent phospholipid scramblase and Ca2+-activated Cl- channel. Inhibition or knockdown of ANO6 attenuates ATP-induced cell shrinkage, cell migration and phospholipid scrambling. In mouse macrophages, Ano6 produces large ion currents by stimulation of P2X7 receptors and contributes to ATP-induced membrane blebbing and apoptosis, which is largely reduced in macrophages from Ano6-/- mice. ANO6 supports bacterial phagocytosis and killing by mouse and human THP-1 macrophages. Our data demonstrate that anoctamin 6 is an essential component of the immune defense by macrophages.

  10. Quantification of In Vitro Macrophage Cholesterol Efflux and In Vivo Macrophage-Specific Reverse Cholesterol Transport.

    PubMed

    Escolà-Gil, Joan Carles; Lee-Rueckert, Miriam; Santos, David; Cedó, Lídia; Blanco-Vaca, Francisco; Julve, Josep

    2015-01-01

    Promotion of reverse cholesterol transport (RCT) is thought to be a major HDL-mediated mechanism for protecting against atherosclerosis. Preclinical studies support the concept that increasing cholesterol efflux from macrophages may confer atheroprotective benefits independently of the plasma HDL-cholesterol concentration. The application of the macrophage-to-feces RCT method in genetically engineered mice has provided evidence that this major HDL property correlates closely with changes in atherosclerosis susceptibility. This chapter provides details on the methodologies currently used to measure in vitro cholesterol efflux from macrophages or in vivo macrophage-specific RCT. The general principles and techniques described herein may be applied to measure the in vitro cholesterol efflux capacity of human serum in macrophage cultures and to evaluate the effect of different experimental pathophysiological conditions or the efficacy of different therapeutic strategies on the modulation of in vivo macrophage-RCT in mice. PMID:26445792

  11. Depression, responsibility, and criminal defenses.

    PubMed

    Hannan, Barbara

    2005-01-01

    The concepts of voluntary action, agency, free will, and responsibility, while central to moral and legal institutions, are generally poorly understood. Philosophers of law such as H.L.A. Hart, Joel Feinberg, and Robert F. Schopp have contributed significantly to understanding of these concepts through their work on the foundations of criminal defenses, including excuses based on mental illness. In this paper, I summarize and present their valuable insights, in the context of an argument (influenced by personal experience) that clinical depression, even when non-psychotic, may in some cases constitute a legitimate excuse for criminal or otherwise immoral failures to act. PMID:15913778

  12. Background issues for defensive interceptors

    SciTech Connect

    Canavan, G.H.

    1991-03-01

    Mean nuclear backgrounds are large, but are arguably amenable to frame-to-frame subtraction. Striated backgrounds on the sensors for defensive interceptors could, however, cause clutter leak-through, which could make detection and track difficult. Nominal motions and backgrounds give signal to clutter ratios too low to be useful. Clutter leakage due to line-of-sight drift can be reduced by stabilizing the line of sight around the background clutter itself. Current interceptors have detector arrays large enough for operation independent of nuclear backgrounds in their fields of view. 6 refs., 2 figs.

  13. 76 FR 21705 - Closed Meeting of the Defense Science Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-18

    ... Pentagon, Arlington, VA. The mission of the Defense Science Board is to advise the Secretary of Defense and..., Defense Science Board, 3140 Defense Pentagon, Room 3B888A, Washington, DC 20301-3140, via e-mail at...

  14. The Metabolic Prospective and Redox Regulation of Macrophage Polarization

    PubMed Central

    He, Chao; Carter, A Brent

    2016-01-01

    Macrophage plasticity is an important feature of these innate immune cells. Macrophage phenotypes are divided into two categories, the classically activated macrophages (CAM, M1 phenotype) and the alternatively activated macrophages (AAM, M2 phenotype). M1 macrophages are commonly associated with the generation of proinflammatory cytokines, whereas M2 macrophages are anti-inflammatory and often associated with tumor progression and fibrosis development. Macrophages produce high levels of reactive oxygen species (ROS). Recent evidence suggests ROS can potentially regulate macrophage phenotype. In addition, macrophages phenotypes are closely related to their metabolic patterns, particularly fatty acid/cholesterol metabolism. In this review, we briefly summarize recent advances in macrophage polarization with special attention to their relevance to specific disease conditions and metabolic regulation of polarization. Understanding these metabolic switches can facilitate the development of targeted therapies for various diseases. PMID:26962470

  15. Complexity of fatty acid distribution inside human macrophages on single cell level using Raman micro-spectroscopy.

    PubMed

    Stiebing, Clara; Matthäus, Christian; Krafft, Christoph; Keller, Andrea-Anneliese; Weber, Karina; Lorkowski, Stefan; Popp, Jürgen

    2014-11-01

    Macrophages are phagocytic cells which are involved in the non-specific immune defense. Lipid uptake and storage behavior of macrophages also play a key role in the development of atherosclerotic lesions within walls of blood vessels. The allocation of exogenous lipids such as fatty acids in the blood stream dictates the accumulation and quantity of lipids within macrophages. In case of an overexposure, macrophages transform into foam cells because of the large amount of lipid droplets in the cytoplasm. Raman micro-spectroscopy is a powerful tool for studying single cells due to the combination of microscopic imaging with spectral information. With a spatial resolution restricted by the diffraction limit, it is possible to visualize lipid droplets within macrophages. With stable isotopic labeling of fatty acids with deuterium, the uptake and storage of exogenously provided fatty acids can be investigated. In this study, we present the results of time-dependent Raman spectroscopic imaging of single THP-1 macrophages incubated with deuterated arachidonic acid. The polyunsaturated fatty acid plays an important role in the cellular signaling pathway as being the precursor of icosanoids. We show that arachidonic acid is stored in lipid droplets but foam cell formation is less pronounced as with other fatty acids. The storage efficiency in lipid droplets is lower than in cells incubated with deuterated palmitic acid. We validate our results with gas chromatography and gain information on the relative content of arachidonic acid and its metabolites in treated macrophages. These analyses also provide evidence that significant amounts of the intracellular arachidonic acid is elongated to adrenic acid but is not metabolized any further. The co-supplementation of deuterated arachidonic acid and deuterated palmitic acid leads to a non-homogenous storage pattern in lipid droplets within single cells. PMID:24939132

  16. Vibrio cholerae porin OmpU mediates M1-polarization of macrophages/monocytes via TLR1/TLR2 activation.

    PubMed

    Khan, Junaid; Sharma, Praveen K; Mukhopadhaya, Arunika

    2015-11-01

    Polarization of the monocytes and macrophages toward the M1 and M2 states is important for hosts' defense against the pathogens. Moreover, it plays a crucial role to resolve the overwhelming inflammatory responses that can be harmful to the host. Polarization of macrophages/monocytes can be induced by pathogen-associated molecular patterns (PAMPs). PAMP-mediated monocyte/macrophage polarization is important during the infection, as pathogen can suppress host immune system by altering the polarization status of the macrophages/monocytes. OmpU, an outer membrane porin protein of Vibrio cholerae, possesses the ability to induce pro-inflammatory responses in monocytes/macrophages. It is also able to down-regulate the LPS-mediated activation of the monocytes/macrophages. Such observation leads us to believe that OmpU may induce a state that can be called as M1/M2-intermediate state. In the present study, we evaluated a set of M1 and M2 markers in RAW 264.7 murine macrophage cell line, and THP-1 human monocytic cell line, in response to the purified OmpU protein. We observed that OmpU, as a PAMP, induced M1-polarization by activating the Toll-like receptor (TLR) signaling pathway. OmpU induced formation of TLR1/TLR2-heterodimers. OmpU-mediated TLR-activation led to the MyD88 recruitment to the TLR1/TLR2 complex. MyD88, in turn, recruited IRAK1. Ultimately, OmpU-mediated signaling led to the activation and subsequent nuclear translocation of the NFκB p65 subunit. We also observed that blocking of the TLR1, TLR2, IRAK1, and NFκB affected OmpU-mediated production of M1-associated pro-inflammatory cytokines such as TNFα and IL-6. PMID:26093918

  17. Contrasting regulation of macrophage iron homeostasis in response to infection with Listeria monocytogenes depending on localization of bacteria.

    PubMed

    Haschka, David; Nairz, Manfred; Demetz, Egon; Wienerroither, Sebastian; Decker, Thomas; Weiss, Günter

    2015-06-01

    Due to its multiple roles for the proliferation and pathogenicity of many microbes on the one hand and via modulation of immune effector functions on the other hand the control over iron homeostasis is thought to play a decisive role in the course of infections. Diversion of cellular iron traffic is considered as an important defense mechanism of macrophages to reduce metal availability for intracellular bacteria residing in the phagosome. However, evidence is lacking whether such alterations of iron homeostasis also become evident upon infection with bacteria gaining access to the cytosol like Listeria monocytogenes. Here we show that infection of macrophages with L. monocytogenes triggers the expression of the major cellular iron exporter ferroportin1 and induces cellular iron egress. As the growth of Listeria within macrophages is promoted by iron, stimulation of ferroportin1 functionality limits the availability of the metal for Listeria residing in the cytoplasm, whereas ferroportin1 degradation upon hepcidin treatment increases intracellular bacterial growth. In parallel to an increase of ferroportin1 expression, infected macrophages induce anti-microbial immune effector mechanisms such as TNFα formation or NO expression which are aggravated upon iron deficiency. These adaptive changes of iron homeostasis and immune response pathways are only found in macrophages infected with Listeria which express listeriolysin O and are therefore able to escape from the phagosome to the cytoplasm. Listeriolysin O deficient Listeria which are restricted to the phagosome are even killed by excess iron which may be based on "iron intoxification" via macrophage radical formation, because iron supplementation in that setting is paralleled by increased ROS formation. Our results indicate that ferroportin1 mediated iron export is a nutritional immune effector pathway to control infection with Listeria residing in the cytoplasm, whereas a different strategy is observed in mutant

  18. Fetuin-A-Containing Calciprotein Particles Reduce Mineral Stress in the Macrophage

    PubMed Central

    Smith, Edward R.; Hanssen, Eric; McMahon, Lawrence P.; Holt, Stephen G.

    2013-01-01

    The formation of fetuin-A-containing calciprotein particles (CPP) may facilitate the clearance of calcium phosphate nanocrystals from the extracellular fluid. These crystals may otherwise seed extra-osseous mineralization. Fetuin-A is a partially phosphorylated glycoprotein that plays a critical role in stabilizing these particles, inhibiting crystal growth and aggregation. CPP removal is thought to be predominantly mediated by cells of the reticuloendothelial system via type I and type II class A scavenger receptor (SR-AI/II). Naked calcium phosphate crystals are known to stimulate macrophages and other cell types in vitro, but little is known of the effect of CPP on these cells. We report here, for the first time, that CPP induce expression and secretion of tumour necrosis factor (TNF)-α, interleukin (IL)-1β in murine RAW 264.7 macrophages. Importantly, however, CPP induced significantly lower cytokine secretion than hydroxyapatite (HAP) crystals of equivalent size and calcium content. Furthermore, CPP only had a modest effect on macrophage viability and apoptosis, even at very high levels, compared to HAP crystals, which were strongly pro-apoptotic at much lower levels. Fetuin-A phosphorylation was found to modulate the effect of CPP on cytokine secretion and apoptosis, but not uptake via SR-AI/II. Prolonged exposure of macrophages to CPP was found to result in up-regulated expression of SR-AI/II. CPP formation may help protect against some of the pro-inflammatory and harmful effects of calcium phosphate nanocrystals, perhaps representing a natural defense system for calcium mineral stress. However, in pathological states where production exceeds clearance capacity, these particles may still stimulate pro-inflammatory and pro-apoptotic cascades in macrophages, which may be important in the pathogenesis of vascular calcification. PMID:23577176

  19. Induction of Rapid Cell Death by an Environmental Isolate of Legionella pneumophila in Mouse Macrophages

    PubMed Central

    Tao, Lili; Zhu, Wenhan; Hu, Bi-Jie

    2013-01-01

    Legionella pneumophila, the etiological agent for Legionnaires' disease, is ubiquitous in the aqueous environment, where it replicates as an intracellular parasite of free-living protozoa. Our understanding of L. pneumophila pathogenicity is obtained mostly from study of derivatives of several clinical isolates, which employ almost identical virulent determinants to exploit host functions. To determine whether environmental L. pneumophila isolates interact similarly with the model host systems, we analyzed intracellular replication of several recently isolated such strains and found that these strains cannot productively grow in bone marrow-derived macrophages of A/J mice, which are permissive for all examined laboratory strains. By focusing on one strain called LPE509, we found that its deficiency in intracellular replication in primary A/J macrophages is not caused by the lack of important pathogenic determinants because this strain replicates proficiently in two protozoan hosts and the human macrophage U937 cell. We also found that in the early phase of infection, the trafficking of this strain in A/J macrophages is similar to that of JR32, a derivative of strain Philadelphia 1. Furthermore, infection of these cells by LPE509 caused extensive cell death in a process that requires the Dot/Icm type IV secretion system. Finally, we showed that the cell death is caused neither by the activation of the NAIP5/NLRC4 inflammasome nor by the recently described caspase 11-dependent pathway. Our results revealed that some environmental L. pneumophila strains are unable to overcome the defense conferred by primary macrophages from mice known to be permissive for laboratory L. pneumophila strains. These results also suggest the existence of a host immune surveillance mechanism differing from those currently known in responding to L. pneumophila infection. PMID:23753633

  20. Alveolar macrophages. II. Inhibition of lymphocyte proliferation by purified macrophages from rat lung.

    PubMed Central

    Holt, P G

    1979-01-01

    Macrophages were prepared from the lung, peritoneal cavity and blood of normal, unstimulated rats from a number of strains. The macrophages were purified by adherence, and characterized via surface markers, enzyme activity and phagocytic capacity, and subsequently tested for activity in cultures of mitogen-stimulated syngeneic lymphocytes. Peritoneal macrophages and blood monocytes were mildly stimulatory, or ineffective in modulating mitogen-induced DNA synthesis; peritoneal macrophages reconstituted the blastogenic responses of macrophage-depleted lymph node cell cultures to normal limits. In contrast, alveolar macrophages were markedly inhibitory to lymphocyte proliferation; in some instances inhibitory activity was demonstrable when added alveolar macrophages comprised only 0.04% of the total cells in culture. Lymphocyte proliferation induced by T-cell mitogens was more susceptible to this inhibition than was proliferation induced by the B-cell mitogen LPS. Alveolar macrophages recovered from SPF rats, while less in number, exhibited comparable inhibitory activity. These results form part of an emerging picture picture of the normal alveolar macrophage as a potential 'suppressor' of T-cell activity in the lung. PMID:468308

  1. The response of macrophages to titanium particles is determined by macrophage polarization.

    PubMed

    Pajarinen, Jukka; Kouri, Vesa-Petteri; Jämsen, Eemeli; Li, Tian-Fang; Mandelin, Jami; Konttinen, Yrjö T

    2013-11-01

    Aseptic loosening of total joint replacements is driven by the reaction of macrophages to foreign body particles released from the implant. It was hypothesized that the macrophages' response to these particles is dependent, in addition to particle characteristics and contaminating biomolecules, on the state of macrophage polarization as determined by the local cytokine microenvironment. To test this hypothesis we differentiated M1 and M2 macrophages from human peripheral blood monocytes and compared their responses to titanium particles using genome-wide microarray analysis and a multiplex cytokine assay. In comparison to non-activated M0 macrophages, the overall chemotactic and inflammatory responses to titanium particles were greatly enhanced in M1 macrophages and effectively suppressed in M2 macrophages. In addition, the genome-wide approach revealed several novel, potentially osteolytic, particle-induced mediators, and signaling pathway analysis suggested the involvement of toll-like and nod-like receptor signaling in particle recognition. It is concluded that the magnitude of foreign body reaction caused by titanium particles is dependent on the state of macrophage polarization. Thus, by limiting the action of M1 polarizing factors, e.g. bacterial biofilm formation, in peri-implant tissues and promoting M2 macrophage polarization by biomaterial solutions or pharmacologically, it might be possible to restrict wear-particle-induced inflammation and osteolysis. PMID:23827094

  2. Autochthonous primary and metastatic melanomas in Hgf-Cdk4 R24C mice evade T-cell-mediated immune surveillance.

    PubMed

    Landsberg, Jennifer; Gaffal, Evelyn; Cron, Mira; Kohlmeyer, Judith; Renn, Marcel; Tüting, Thomas

    2010-10-01

    Genetically engineered mouse models offer new opportunities to investigate the role of cell-mediated immunity in the natural progression of melanoma in an immunocompetent host. Here we report that Hgf-Cdk4(R24C) mice spontaneously develop a spectrum of primary melanomas with high penetrance during their first year of life. Malignant transformation proceeds in a stepwise manner from multiple melanocytic nevi to single nodular melanomas and disseminated metastases in most mice. Migrating melanoma cells invade the draining lymph nodes without activating the immune system. Autochthonous primary tumors are destroyed following experimental introduction of immune surveillance using an adoptive lymphocyte transfer approach. However, some tumor cells are able to survive, evade immune cell control, and recur both locally and systemically. Immune tolerance in recurring tumors may be supported by immunosuppressive Gr1(+) myeloid cells. Taken together, our results demonstrate that primary and metastatic melanomas developing spontaneously in Hgf-Cdk4(R24C) mice effectively evade cellular immune surveillance. PMID:20649939

  3. Biogeography of a defensive symbiosis

    PubMed Central

    Kaltenpoth, Martin; Roeser-Mueller, Kerstin; Stubblefield, J. William; Seger, Jon; Strohm, Erhard

    2014-01-01

    Mutualistic microorganisms play important roles in nutrition, reproduction and defense of many insects, yet the factors contributing to their maintenance and dispersal remain unknown in most cases. Theory suggests that collaboration can be maintained by repeated interaction of the same partners (partner fidelity) or by selective discrimination against non-cooperative partners (partner choice). In the defensive mutualism between solitary beewolf wasps and their antibiotic-producing Streptomyces bacteria, partner choice by host control of vertical symbiont transmission reinforces partner fidelity and has helped to maintain this highly specific association since it originated in the late Cretaceous. However, co-phylogenetic and biogeographic analyses suggest that there has also been considerable horizontal transmission of the symbionts. While the beewolves clearly have a paleotropic or palearctic origin, with later colonization of the nearctic and neotropics via Beringia and the Aves ridge, respectively, the bacteria show only weak geographical clustering, implying global dispersal or vicariance within the confines of an otherwise apparently exclusive symbiotic relationship. We discuss several hypotheses that may explain these patterns. Future studies investigating the occurrence of beewolf symbionts in the environment could yield broadly applicable insights into the relative impact of animal-vectored and free-living dispersal on the distribution of microorganisms in nature. PMID:26479018

  4. Defense mutualisms enhance plant diversification.

    PubMed

    Weber, Marjorie G; Agrawal, Anurag A

    2014-11-18

    The ability of plants to form mutualistic relationships with animal defenders has long been suspected to influence their evolutionary success, both by decreasing extinction risk and by increasing opportunity for speciation through an expanded realized niche. Nonetheless, the hypothesis that defense mutualisms consistently enhance plant diversification across lineages has not been well tested due to a lack of phenotypic and phylogenetic information. Using a global analysis, we show that the >100 vascular plant families in which species have evolved extrafloral nectaries (EFNs), sugar-secreting organs that recruit arthropod mutualists, have twofold higher diversification rates than families that lack species with EFNs. Zooming in on six distantly related plant clades, trait-dependent diversification models confirmed the tendency for lineages with EFNs to display increased rates of diversification. These results were consistent across methodological approaches. Inference using reversible-jump Markov chain Monte Carlo (MCMC) to model the placement and number of rate shifts revealed that high net diversification rates in EFN clades were driven by an increased number of positive rate shifts following EFN evolution compared with sister clades, suggesting that EFNs may be indirect facilitators of diversification. Our replicated analysis indicates that defense mutualisms put lineages on a path toward increased diversification rates within and between clades, and is concordant with the hypothesis that mutualistic interactions with animals can have an impact on deep macroevolutionary patterns and enhance plant diversity. PMID:25349406

  5. Defense mutualisms enhance plant diversification

    PubMed Central

    Weber, Marjorie G.; Agrawal, Anurag A.

    2014-01-01

    The ability of plants to form mutualistic relationships with animal defenders has long been suspected to influence their evolutionary success, both by decreasing extinction risk and by increasing opportunity for speciation through an expanded realized niche. Nonetheless, the hypothesis that defense mutualisms consistently enhance plant diversification across lineages has not been well tested due to a lack of phenotypic and phylogenetic information. Using a global analysis, we show that the >100 vascular plant families in which species have evolved extrafloral nectaries (EFNs), sugar-secreting organs that recruit arthropod mutualists, have twofold higher diversification rates than families that lack species with EFNs. Zooming in on six distantly related plant clades, trait-dependent diversification models confirmed the tendency for lineages with EFNs to display increased rates of diversification. These results were consistent across methodological approaches. Inference using reversible-jump Markov chain Monte Carlo (MCMC) to model the placement and number of rate shifts revealed that high net diversification rates in EFN clades were driven by an increased number of positive rate shifts following EFN evolution compared with sister clades, suggesting that EFNs may be indirect facilitators of diversification. Our replicated analysis indicates that defense mutualisms put lineages on a path toward increased diversification rates within and between clades, and is concordant with the hypothesis that mutualistic interactions with animals can have an impact on deep macroevolutionary patterns and enhance plant diversity. PMID:25349406

  6. Verification of excess defense material

    SciTech Connect

    Fearey, B.L.; Pilat, J.F.; Eccleston, G.W.; Nicholas, N.J.; Tape, J.W.

    1997-12-01

    The international community in the post-Cold War period has expressed an interest in the International Atomic Energy Agency (IAEA) using its expertise in support of the arms control and disarmament process in unprecedented ways. The pledges of the US and Russian presidents to place excess defense materials under some type of international inspections raises the prospect of using IAEA safeguards approaches for monitoring excess materials, which include both classified and unclassified materials. Although the IAEA has suggested the need to address inspections of both types of materials, the most troublesome and potentially difficult problems involve approaches to the inspection of classified materials. The key issue for placing classified nuclear components and materials under IAEA safeguards is the conflict between these traditional IAEA materials accounting procedures and the US classification laws and nonproliferation policy designed to prevent the disclosure of critical weapon-design information. Possible verification approaches to classified excess defense materials could be based on item accountancy, attributes measurements, and containment and surveillance. Such approaches are not wholly new; in fact, they are quite well established for certain unclassified materials. Such concepts may be applicable to classified items, but the precise approaches have yet to be identified, fully tested, or evaluated for technical and political feasibility, or for their possible acceptability in an international inspection regime. Substantial work remains in these areas. This paper examines many of the challenges presented by international inspections of classified materials.

  7. Macrophagic myofasciitis: an infantile Italian case.

    PubMed

    Di Muzio, A; Capasso, M; Verrotti, A; Trotta, D; Lupo, S; Pappalepore, N; Manzoli, C; Chiarelli, F; Uncini, A

    2004-02-01

    Macrophagic myofasciitis is a recently identified inflammatory myopathy mostly described in adult French patients complaining of arthro-myalgias and fatigue. It is probably due to intramuscular injection of aluminium-containing vaccines and is characterized by a typical muscular infiltrate of large macrophages with aluminium inclusions. We report a 1-year-old Italian child presenting irritability, delayed motor development, hyperCKemia (up to 10 times the normal value), and typical features of macrophagic myofasciitis on muscle biopsy. The child recovered fully after steroid therapy. Macrophagic myofasciitis is a new treatable cause of motor retardation and hyperCKemia in children, and is probably more common than reported. Diagnosis requires a high index of suspicion and can be missed if biopsy is performed outside the vaccination site. PMID:14733966

  8. Generation and Characterization of Mouse Regulatory Macrophages.

    PubMed

    Carretero-Iglesia, Laura; Hill, Marcelo; Cuturi, Maria Cristina

    2016-01-01

    In the last years, cell therapy has become a promising approach to therapeutically manipulate immune responses in autoimmunity, cancer, and transplantation. Several types of lymphoid and myeloid cells origin have been generated in vitro and tested in animal models. Their efficacy to decrease pharmacological treatment has successfully been established. Macrophages play an important role in physiological and pathological processes. They represent an interesting cell population due to their high plasticity in vivo and in vitro. Here, we describe a protocol to differentiate murine regulatory macrophages in vitro from bone marrow precursors. We also describe several methods to assess macrophage classical functions, as their bacterial killing capacity and antigen endocytosis and degradation. Importantly, regulatory macrophages also display suppressive characteristics, which are addressed by the study of their hypostimulatory T lymphocyte capacity and polyclonal T lymphocyte activation suppression. PMID:26530796

  9. Macrophages in Vascular Inflammation: Origins and Functions.

    PubMed

    Decano, Julius L; Mattson, Peter C; Aikawa, Masanori

    2016-06-01

    Macrophages influence various processes of cardiovascular inflammation. Whether they are of embryonic or post-natal hematopoietic origin, their balance in differential activation may direct the course of inflammation. Accelerated macrophage activation and accumulation through a pro-inflammatory signaling pathway may result in extensive tissue damage, adverse repair, and worsened clinical outcomes. Attenuation of such a mechanism and/or promotion of the anti-inflammatory macrophage activation may lead to early resolution of inflammation. Elucidating multiple novel mechanisms of monocyte and macrophage activation leads to a better understanding of their roles in vascular inflammation. In turn, this begets better therapeutic target identification and biomarker discovery. Combined with increasingly sensitive and specific imaging techniques, we continue to push back early detection and monitoring to provide us with a greater window for disease modification. The potential success of cytokine-targeted therapy will be solid proof of the inflammatory hypothesis of atherothrombosis. PMID:27125207

  10. Defensive weapons and defense signals in plants: some metabolites serve both roles.

    PubMed

    Maag, Daniel; Erb, Matthias; Köllner, Tobias G; Gershenzon, Jonathan

    2015-02-01

    The defense of plants against herbivores and pathogens involves the participation of an enormous range of different metabolites, some of which act directly as defensive weapons against enemies (toxins or deterrents) and some of which act as components of the complex internal signaling network that insures that defense is timed to enemy attack. Recent work reveals a surprising trend: The same compounds may act as both weapons and signals of defense. For example, two groups of well-studied defensive weapons, glucosinolates and benzoxazinoids, trigger the accumulation of the protective polysaccharide callose as a barrier against aphids and pathogens. In the other direction, several hormones acting in defense signaling (and their precursors and products) exhibit activity as weapons against pathogens. Knowing which compounds are defensive weapons, which are defensive signals and which are both is vital for understanding the functioning of plant defense systems. PMID:25389065

  11. 76 FR 60812 - Defense Business Board (DBB); Meeting Notice

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ... of the Secretary Defense Business Board (DBB); Meeting Notice AGENCY: Department of Defense (DoD... meeting of the Defense Business Board (DBB). DATES: The public meeting of the Defense Business Board...: Ms. Debora Duffy, Defense Business Board, 1155 Defense Pentagon, Room 5B1088A, Washington, DC...

  12. 32 CFR 150.10 - Request for appellate defense counsel.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 1 2012-07-01 2012-07-01 false Request for appellate defense counsel. 150.10 Section 150.10 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE REGULATIONS... for appellate defense counsel. An accused may be represented before the Court by appellate...

  13. 32 CFR 28.500 - Secretary of Defense.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 1 2011-07-01 2011-07-01 false Secretary of Defense. 28.500 Section 28.500 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... making such a determination. (b) Policy. It is the policy of the Department of Defense that...

  14. 32 CFR 150.10 - Request for appellate defense counsel.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 1 2011-07-01 2011-07-01 false Request for appellate defense counsel. 150.10 Section 150.10 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE REGULATIONS... for appellate defense counsel. An accused may be represented before the Court by appellate...

  15. 32 CFR 150.10 - Request for appellate defense counsel.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 1 2013-07-01 2013-07-01 false Request for appellate defense counsel. 150.10 Section 150.10 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE REGULATIONS... for appellate defense counsel. An accused may be represented before the Court by appellate...

  16. 32 CFR 150.10 - Request for appellate defense counsel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Request for appellate defense counsel. 150.10 Section 150.10 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE REGULATIONS PERTAINING TO MILITARY JUSTICE COURTS OF CRIMINAL APPEALS RULES OF PRACTICE AND PROCEDURE § 150.10 Request for appellate defense counsel. An...

  17. 32 CFR 28.500 - Secretary of Defense.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 1 2014-07-01 2014-07-01 false Secretary of Defense. 28.500 Section 28.500 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... making such a determination. (b) Policy. It is the policy of the Department of Defense that...

  18. 32 CFR 28.500 - Secretary of Defense.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 1 2012-07-01 2012-07-01 false Secretary of Defense. 28.500 Section 28.500 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... making such a determination. (b) Policy. It is the policy of the Department of Defense that...

  19. 32 CFR 150.10 - Request for appellate defense counsel.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 1 2014-07-01 2014-07-01 false Request for appellate defense counsel. 150.10 Section 150.10 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE REGULATIONS... for appellate defense counsel. An accused may be represented before the Court by appellate...

  20. 32 CFR 28.500 - Secretary of Defense.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 1 2013-07-01 2013-07-01 false Secretary of Defense. 28.500 Section 28.500 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... making such a determination. (b) Policy. It is the policy of the Department of Defense that...