Neutrophil extracellular traps: casting the NET over pathogenesis

Department of Bacteriology, Swedish Institute for Infectious Disease Control Nobelsväg 18, SE-171 82 Solna, Solna, Sweden.
Current Opinion in Microbiology (Impact Factor: 7.22). 03/2007; 10(1):52-6. DOI: 10.1016/j.mib.2006.12.005
Source: PubMed

ABSTRACT Neutrophil extracellular traps (NETs) are considered to be part of the human innate immunity because they trap and kill pathogens. NETs are formed by activated neutrophils and consist of a DNA backbone with embedded antimicrobial peptides and enzymes. They are involved in host defense during pneumococcal pneumonia, streptococcal necrotizing fasciitis, appendicitis and insemination. Recently, bacterial virulence factors that counteract NETs have been identified. These include the degradation of the NET-backbone by DNases enabling the liberation of bacteria from NETs, as well as capsule formation, which reduces bacterial trapping. Furthermore, pathogens can resist NET-mediated killing by adding positive charge to their cell surface.

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    • "survival of GAS when entangled in neutrophil extracellular traps (NETs) (Buchanan et al., 2006; de Buhr et al., 2014; Wartha et al., 2007). The interaction between GAS phage and non-phage genes and their products is an evolving field that is bound to shed important new light on the pathogenesis of GAS infections. "
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    ABSTRACT: Streptococcus pyogenes (group A Streptococcus; GAS) is a strict human pathogen with a very high prevalence worldwide. This review highlights the genetic organization of the species and the important ecological considerations that impact its evolution. Recent advances are presented on the topics of molecular epidemiology, population biology, molecular basis for genetic change, genome structure and genetic flux, phylogenomics and closely related streptococcal species, and the long- and short-term evolution of GAS. The application of whole genome sequence data to addressing key biological questions is discussed.
    Infection Genetics and Evolution 10/2014; 33. DOI:10.1016/j.meegid.2014.10.011 · 3.26 Impact Factor
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    • "In this regard, exDNA has long been known in many biological secretions including bacterial biofilms, snail mucigels, and white human blood cell matrices where it localizes with a number of antimicrobial peptides and proteins (Fahy et al. 1993; Allesen-Holm et al. 2006). In the case of human neutrophils, such a complex called also the NET " neutrophil extracellular trap " is capable of protecting the cells against pathogens at the sites of infection (Wartha et al. 2007; Guimarães-Costa et al. 2009 "
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    ABSTRACT: Production and release of root border cells and border-like cells are fundamental processes for plant survival and development. Both types of cells are viable components of the root system that regulate its interactions with living microorganisms of the rhizosphere. Border cells are released as individual cells, whereas border-like cells remain attached to each other into small groups or as sheets after their release from the root tip. So far, border-like cells have been observed only in species belonging to the Brassicaceae family including Arabidopsis. Border cells have been largely studied in the legume species pea; in contrast, relatively little information is available on border-like cells so far due to their recent discovery. In this chapter, we present and discuss the release, organization, and the role of these cells in root protection.
    Secretions and exudates in biological systems, Springer-Verlag Berlin Heidelberg edited by Jorge M. Vivanco, František Baluška, 01/2012: pages 91-107; Springer Berlin Heidelberg., ISBN: 978-3-642-23046-2
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    • "In mammals, it is now well established that exDNA from blood cells such as neutrophils, eosinophils and mast cells plays a major role in defence against microbial pathogen invasion. Upon infection, exDNA with extracellular peptides and proteins forms a complex neutrophil extracellular trap called 'NET' that aggregates and kills the pathogens (Wartha et al., 2007; Medina, 2009). In peas, the digestion of exDNA from root border-cell exudate using enzymes such as DNase I results in loss of root tip resistance to N. haematococca infection (Wen et al., 2009). "
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    ABSTRACT: The oomycete Aphanomyces euteiches causes up to 80 % crop loss in pea (Pisum sativum). Aphanomyces euteiches invades the root system leading to a complete arrest of root growth and ultimately to plant death. To date, disease control measures are limited to crop rotation and no resistant pea lines are available. The present study aims to get a deeper understanding of the early oomycete-plant interaction at the tissue and cellular levels. Here, the process of root infection by A. euteiches on pea is investigated using flow cytometry and microscopic techniques. Dynamic changes in secondary metabolism are analysed with high-performance liquid chromatography with diode-array detection. Root infection is initiated in the elongation zone but not in the root cap and border cells. Border-cell production is significantly enhanced in response to root inoculation with changes in their size and morphology. The stimulatory effect of A. euteiches on border-cell production is dependent on the number of oospores inoculated. Interestingly, border cells respond to pathogen challenge by increasing the synthesis of the phytoalexin pisatin. Distinctive responses to A. euteiches inoculation occur at the root tissue level. The findings suggest that root border cells in pea are involved in local defence of the root tip against A. euteiches. Root border cells constitute a convenient quantitative model to measure the molecular and cellular basis of plant-microbe interactions.
    Annals of Botany 09/2011; 108(3):459-69. DOI:10.1093/aob/mcr177 · 3.30 Impact Factor
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