scholarly journals Neisseria gonorrhoeae Elicits Extracellular Traps in Primary Neutrophil Culture While Suppressing the Oxidative Burst

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Carl W. Gunderson ◽  
H. Steven Seifert
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Oxidative Burst ◽  
Bacterial Species ◽  
Immune Surveillance ◽  
Large Body ◽  
Surface Antigens ◽  
Neutrophil Extracellular Traps ◽  
Content Type ◽  
Extracellular Traps ◽  
Variable Surface

ABSTRACT Neisseria gonorrhoeae(the gonococcus) causes gonorrhea and is uniquely adapted to survive within the human reproductive tract. Gonococci evade host immune surveillance in part by varying their pili and opacity-associated proteins. These variable surface antigens influence interactions with host epithelial and immune cells. A potent polymorphonuclear leukocyte (PMN) response is a hallmark of symptomatic gonococcal infection, with vast numbers of PMNs recruited to the site of infection. A large body of literature describes gonococcus-PMN interactions, but the factors driving the outcome of infection are not fully understood. Gonococci have been described to both induce and suppress the PMN oxidative burst, but we determined that gonococci differentially affect induction of the PMN oxidative burst depending on the multiplicity of infection (MOI). Infecting PMN at an MOI of <20 gonococci elicits an oxidative burst, while an MOI of >20 suppresses the burst. Oxidative burst in response to gonococci is enhanced by, but does not require, expression of pili or opacity proteins. Neutrophil extracellular traps (NETs) were observed in gonococcus-infected PMNs, a process which requires an oxidative burst, yet gonococci induced NETs under suppressing conditions. The NETs were unable to kill gonococci despite killing the common vaginal bacteriumLactobacillus crispatus. Thus, gonococci influence PMN biology to promote their own survival by suppressing the oxidative burst of PMNs and stimulating the formation of NETs, which do not effectively kill gonococci, illustrating how N. gonorrhoeae has evolved to modulate PMN responses to promote infection.IMPORTANCE Neisseria gonorrhoeae, the gonococcus, is the only causative agent of gonorrhea and is exclusively found within the human host. Gonococci stochastically vary the composition of antigens on their surface to evade immune surveillance. We used gonococcal mutants which stably express different surface antigens to dissect interactions between gonococci and primary human polymorphonuclear leukocytes (PMNs). We found that gonococci, depending on the number of bacteria present, either induce or suppress the oxidative burst of PMNs regardless of other stimuli. Gonococci also cause PMNs to release DNA, forming neutrophil extracellular traps (NETs) independently of the oxidative burst. The NETs were unable to kill gonococci but were able to kill commensal bacteria, suggesting that NET production can help gonococci outcompete other bacterial species. We propose that gonococci have evolved to manipulate PMN responses to promote their own survival during infection.

scholarly journals Neisseria gonorrhoeae Evades Calprotectin-Mediated Nutritional Immunity and Survives Neutrophil Extracellular Traps by Production of TdfH

2016 ◽  
Vol 84 (10) ◽  
pp. 2982-2994 ◽  
Author(s):  
Sophonie Jean ◽  
Richard A. Juneau ◽  
Alison K. Criss ◽  
Cynthia N. Cornelissen
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Defense Mechanism ◽  
Outer Membrane Proteins ◽  
Neutrophil Extracellular Traps ◽  
Host Protein ◽  
Dependent Manner ◽  
Bacterial Survival ◽  
Content Type ◽  
Extracellular Traps ◽  
Nutritional Immunity

Neisseria gonorrhoeaesuccessfully overcomes host strategies to limit essential nutrients, termed nutritional immunity, by production of TonB-dependent transporters (TdTs)—outer membrane proteins that facilitate nutrient transport in an energy-dependent manner. Four gonococcal TdTs facilitate utilization of iron or iron chelates from host-derived proteins, including transferrin (TbpA), lactoferrin (LbpA), and hemoglobin (HpuB), in addition to xenosiderophores from other bacteria (FetA). The roles of the remaining four uncharacterized TdTs (TdfF, TdfG, TdfH, and TdfJ) remain elusive. Regulatory data demonstrating that production of gonococcal TdfH and TdfJ are unresponsive to or upregulated under iron-replete conditions led us to evaluate the role of these TdTs in the acquisition of nutrients other than iron. In this study, we found that production of gonococcal TdfH is both Zn and Zur repressed. We also found that TdfH confers resistance to calprotectin, an immune effector protein highly produced in neutrophils that has antimicrobial activity due to its ability to sequester Zn and Mn. We found that TdfH directly binds calprotectin, which enables gonococcal Zn accumulation in a TdfH-dependent manner and enhances bacterial survival after exposure to neutrophil extracellular traps (NETs). These studies highlight Zn sequestration by calprotectin as a key functional arm of NET-mediated killing of gonococci. We demonstrate for the first time thatN. gonorrhoeaeexploits this host strategy in a novel defense mechanism, in which TdfH production hijacks and directly utilizes the host protein calprotectin as a zinc source and thereby evades nutritional immunity.

scholarly journals Neutrophil Extracellular Traps Exhibit Antibacterial Activity against Burkholderia pseudomallei and Are Influenced by Bacterial and Host Factors

2012 ◽  
Vol 80 (11) ◽  
pp. 3921-3929 ◽  
Author(s):  
Donporn Riyapa ◽  
Surachat Buddhisa ◽  
Sunee Korbsrisate ◽  
Jon Cuccui ◽  
Brendan W. Wren ◽  
...  
Keyword(s):  
Burkholderia Pseudomallei ◽  
Capsular Polysaccharide ◽  
Neutrophil Extracellular Traps ◽  
Polymorphonuclear Neutrophils ◽  
Dependent Manner ◽  
Predisposing Factor ◽  
Bacterial Killing ◽  
Content Type ◽  
Extracellular Traps ◽  
Type Iii Protein Secretion

ABSTRACTBurkholderia pseudomalleiis the causative pathogen of melioidosis, of which a major predisposing factor is diabetes mellitus. Polymorphonuclear neutrophils (PMNs) kill microbes extracellularly by the release of neutrophil extracellular traps (NETs). PMNs play a key role in the control of melioidosis, but the involvement of NETs in killing ofB. pseudomalleiremains obscure. Here, we showed that bactericidal NETs were released from human PMNs in response toB. pseudomalleiin a dose- and time-dependent manner.B. pseudomallei-induced NET formation required NADPH oxidase activation but not phosphatidylinositol-3 kinase, mitogen-activated protein kinases, or Src family kinase signaling pathways.B. pseudomalleimutants defective in the virulence-associated Bsa type III protein secretion system (T3SS) or capsular polysaccharide I (CPS-I) induced elevated levels of NETs. NET induction by such mutants was associated with increased bacterial killing, phagocytosis, and oxidative burst by PMNs. Taken together the data imply that T3SS and the capsule may play a role in evading the induction of NETs. Importantly, PMNs from diabetic subjects released NETs at a lower level than PMNs from healthy subjects. Modulation of NET formation may therefore be associated with the pathogenesis and control of melioidosis.

scholarly journals Heparan Sulfate Modulates Neutrophil and Endothelial Function in Antibacterial Innate Immunity

2015 ◽  
Vol 83 (9) ◽  
pp. 3648-3656 ◽  
Author(s):  
Ding Xu ◽  
Joshua Olson ◽  
Jason N. Cole ◽  
Xander M. van Wijk ◽  
Volker Brinkmann ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Heparan Sulfate ◽  
Bactericidal Activity ◽  
Bacterial Pathogen ◽  
Systemic Infection ◽  
Neutrophil Extracellular Traps ◽  
Content Type ◽  
Extracellular Traps ◽  
The Central Nervous System ◽  
Group B

Recently, we showed that endothelial heparan sulfate facilitates entry of a bacterial pathogen into the central nervous system. Here, we show that normal bactericidal activity of neutrophils is influenced by the sulfation pattern of heparan sulfate. Inactivation of heparan sulfate uronyl 2-O-sulfotransferase (Hs2st) in neutrophils substantially reduced their bactericidal activity, and Hs2st deficiency rendered mice more susceptible to systemic infection with the pathogenic bacterium group BStreptococcus. Specifically, altered sulfation of heparan sulfate in mutant neutrophils affected formation of neutrophil extracellular traps while not influencing phagocytosis, production of reactive oxygen species, or secretion of granular proteases. Heparan sulfate proteoglycan(s) is present in neutrophil extracellular traps, modulates histone affinity, and modulates their microbial activity. Hs2st-deficient brain endothelial cells show enhanced binding to group BStreptococcusand are more susceptible to apoptosis, likely contributing to the observed increase in dissemination of group BStreptococcusinto the brain of Hs2st-deficient mice following intravenous challenge. Taken together, our data provide strong evidence that heparan sulfate from both neutrophils and the endothelium plays important roles in modulating innate immunity.

scholarly journals Discovery of a New Neisseria gonorrhoeae Type IV Pilus Assembly Factor, TfpC

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Linda I. Hu ◽  
Shaohui Yin ◽  
Egon A. Ozer ◽  
Lee Sewell ◽  
Saima Rehman ◽  
...  
Keyword(s):  
Cell Surface ◽  
Neisseria Gonorrhoeae ◽  
Bacterial Cell ◽  
Bacterial Species ◽  
Type Iv Pili ◽  
Type Iv Pilus ◽  
Transmitted Infection ◽  
Content Type ◽  
Sexually Transmitted ◽  
Type Iv

ABSTRACT Neisseria gonorrhoeae relies on type IV pili (T4p) to promote colonization of their human host and to cause the sexually transmitted infection gonorrhea. This organelle cycles through a process of extension and retraction back into the bacterial cell. Through a genetic screen, we identified the NGO0783 locus of N. gonorrhoeae strain FA1090 as containing a gene encoding a protein required to stabilize the type IV pilus in its extended, nonretracted conformation. We have named the gene tfpC and the protein TfpC. Deletion of tfpC produces a nonpiliated colony morphology, and immuno-transmission electron microscopy confirms that the pili are lost in the ΔtfpC mutant, although there is some pilin detected near the bacterial cell surface. A copy of the tfpC gene expressed from a lac promoter restores pilus expression and related phenotypes. A ΔtfpC mutant shows reduced levels of pilin protein, but complementation with a tfpC gene restored pilin to normal levels. Bioinformatic searches show that there are orthologues in numerous bacterial species, but not all type IV pilin-expressing bacteria contain orthologous genes. Coevolution and nuclear magnetic resonance (NMR) analysis indicates that TfpC contains an N-terminal transmembrane helix, a substantial extended/unstructured region, and a highly charged C-terminal coiled-coil domain. IMPORTANCE Most bacterial species express one or more extracellular organelles called pili/fimbriae that are required for many properties of each bacterial cell. The Neisseria gonorrhoeae type IV pilus is a major virulence and colonization factor for the sexually transmitted infection gonorrhea. We have discovered a new protein of Neisseria gonorrhoeae called TfpC that is required to maintain type IV pili on the bacterial cell surface. There are similar proteins found in other members of the Neisseria genus and many other bacterial species important for human health.

scholarly journals Degraded neutrophil extracellular traps promote the growth of Actinobacillus pleuropneumoniae

2019 ◽  
Vol 10 (9) ◽  
Author(s):  
Nicole de Buhr ◽  
Marta C. Bonilla ◽  
Jessica Pfeiffer ◽  
Silke Akhdar ◽  
Cornelia Schwennen ◽  
...  
Keyword(s):  
Immune Cell ◽  
Bacterial Species ◽  
Severe Pneumonia ◽  
Lavage Fluid ◽  
Neutrophil Extracellular Traps ◽  
Actinobacillus Pleuropneumoniae ◽  
Degraded Dna ◽  
Human Neutrophils ◽  
Extracellular Traps

Abstract Actinobacillus pleuropneumoniae (A.pp) causes severe pneumonia associated with enormous economic loss in pigs. Peracute diseased pigs die in <24 h with pneumonia. Neutrophils are the prominent innate immune cell in this infection that massively infiltrate the infected lung. Here we show that neutrophils release neutrophil extracellular traps (NETs) as response to A.pp infection. Numerous NET-markers were identified in bronchoalveolar lavage fluid (BALF) of A.pp-infected piglets in vivo, however, most NET fibers are degraded. Importantly, A.pp is able to enhance its growth rate in the presence of NETs that have been degraded by nucleases efficiently. A.pp itself releases no nuclease, but we identified host nucleases as sources that degrade NETs after A.pp infection. Furthermore, the nucleases of co-infecting pathogens like Streptococcus suis increase growth of A.pp in presence of porcine NETs. Thus, A.pp is not only evading the antimicrobial activity of NETs, A.pp is rather additionally using parts of NETs as growth factor thereby taking advantage of host nucleases as DNase1 or nucleases of co-infecting bacteria, which degrade NETs. This effect can be diminished by inhibiting the bacterial adenosine synthase indicating that degraded NETs serve as a source for NAD, which is required by A.pp for its growth. A similar phenotype was found for the human pathogen Haemophilus (H.) influenzae and its growth in the presence of human neutrophils. H. influenzae benefits from host nucleases in the presence of neutrophils. These data shed light on the detrimental effects of NETs during host immune response against certain bacterial species that require and/or efficiently take advantage of degraded DNA material, which has been provided by host nuclease or nucleases of other co-infecting bacteria, as growth source.

scholarly journals A DNase from a Fungal Phytopathogen Is a Virulence Factor Likely Deployed as Counter Defense against Host-Secreted Extracellular DNA

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Hee-Jin Park ◽  
Weiwei Wang ◽  
Gilberto Curlango-Rivera ◽  
Zhongguo Xiong ◽  
Zeran Lin ◽  
...  
Keyword(s):  
Single Gene ◽  
Neutrophil Extracellular Traps ◽  
Extracellular Dna ◽  
Fungal Culture ◽  
Wild Type ◽  
Plant Host ◽  
Gene Encoding ◽  
Content Type ◽  
Extracellular Traps ◽  
Fungal Plant Pathogen

ABSTRACT Histone-linked extracellular DNA (exDNA) is a component of neutrophil extracellular traps (NETs). NETs have been shown to play a role in immune response to bacteria, fungi, viruses, and protozoan parasites. Mutation of genes encoding group A Streptococcus extracellular DNases (exDNases) results in reduced virulence in animals, a finding that implies that exDNases are deployed as counter defense against host DNA-containing NETs. Is the exDNA/exDNase mechanism also relevant to plants and their pathogens? It has been demonstrated previously that exDNA is a component of a matrix secreted from plant root caps and that plants also carry out an extracellular trapping process. Treatment with DNase I destroys root tip resistance to infection by fungi, the most abundant plant pathogens. We show that the absence of a single gene encoding a candidate exDNase results in significantly reduced virulence of a fungal plant pathogen to its host on leaves, the known infection site, and on roots. Mg2+-dependent exDNase activity was demonstrated in fungal culture filtrates and induced when host leaf material was present. It is speculated that the enzyme functions to degrade plant-secreted DNA, a component of a complex matrix akin to neutrophil extracellular traps of animals. IMPORTANCE We document that the absence of a single gene encoding a DNase in a fungal plant pathogen results in significantly reduced virulence to a plant host. We compared a wild-type strain of the maize pathogen Cochliobolus heterostrophus and an isogenic mutant lacking a candidate secreted DNase-encoding gene and demonstrated that the mutant is reduced in virulence on leaves and on roots. There are no previous reports of deletion of such a gene from either an animal or plant fungal pathogen accompanied by comparative assays of mutants and wild type for alterations in virulence. We observed DNase activity, in fungal culture filtrates, that is Mg2+ dependent and induced when plant host leaf material is present. Our findings demonstrate not only that fungi use extracellular DNases (exDNases) for virulence, but also that the relevant molecules are deployed in above-ground leaves as well as below-ground plant tissues. Overall, these data provide support for a common defense/counter defense virulence mechanism used by animals, plants, and their fungal and bacterial pathogens and suggest that components of the mechanism might be novel targets for the control of plant disease.

scholarly journals NontypeableHaemophilus influenzaeInitiates Formation of Neutrophil Extracellular Traps

2010 ◽  
Vol 79 (1) ◽  
pp. 431-438 ◽  
Author(s):  
Richard A. Juneau ◽  
Bing Pang ◽  
Kristin E. D. Weimer ◽  
Chelsie E. Armbruster ◽  
W. Edward Swords
Keyword(s):  
Otitis Media ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
Neutrophil Extracellular Traps ◽  
Bacterial Surface ◽  
Persistent Infections ◽  
Extracellular Traps ◽  
Molecular Patterns

ABSTRACTNontypeableHaemophilus influenzae(NTHI) is a leading cause of otitis media infections, which are often chronic and/or recurrent in nature. NTHI and other bacterial species persistin vivowithin biofilms during otitis media and other persistent infections. These biofilms have a significant host component that includes neutrophil extracellular traps (NETs). These NETs do not mediate clearance of NTHI, which survives within NET structures by means of specific subpopulations of lipooligosaccharides on the bacterial surface that are determinants of biofilm formationin vitro. In this study, the ability of NTHI and NTHI components to initiate NET formation was examined using anin vitromodel system. Both viable and nonviable NTHI strains were shown to promote NET formation, as did preparations of bacterial DNA, outer membrane proteins, and lipooligosaccharide (endotoxin). However, only endotoxin from a parental strain of NTHI exhibited equivalent potency in NET formation to that of NTHI. Additional studies showed that NTHI entrapped within NET structures is resistant to both extracellular killing within NETs and phagocytic killing by incoming neutrophils, due to oligosaccharide moieties within the lipooligosaccharides. Thus, we concluded that NTHI elicits NET formation by means of multiple pathogen-associated molecular patterns (most notably endotoxin) and is highly resistant to killing within NET structures. These data support the conclusion that, for NTHI, formation of NET structures may be a persistence determinant by providing a niche within the middle-ear chamber.

scholarly journals 3′-Nucleotidase/Nuclease Activity Allows Leishmania Parasites To Escape Killing by Neutrophil Extracellular Traps

2014 ◽  
Vol 82 (4) ◽  
pp. 1732-1740 ◽  
Author(s):  
Anderson B. Guimarães-Costa ◽  
Thiago S. DeSouza-Vieira ◽  
Rafael Paletta-Silva ◽  
Anita Leocádio Freitas-Mesquita ◽  
José Roberto Meyer-Fernandes ◽  
...  
Keyword(s):  
Leishmania Infantum ◽  
Nuclease Activity ◽  
Neutrophil Extracellular Traps ◽  
Human Neutrophils ◽  
Dependent Manner ◽  
Content Type ◽  
Extracellular Traps ◽  
Leishmania Parasites ◽  
High Phosphate

ABSTRACTLeishmaniasis is a widespread neglected tropical disease caused by parasites of theLeishmaniagenus. These parasites express the enzyme 3′-nucleotidase/nuclease (3′NT/NU), which has been described to be involved in parasite nutrition and infection. Bacteria that express nucleases escape the toxic effects of neutrophil extracellular traps (NETs). Hence, we investigated the role of 3′NT/NU inLeishmaniasurvival of NET-mediated killing. Promastigotes ofLeishmania infantumwere cultured in high-phosphate (HP) or low-phosphate (LP) medium to modulate nuclease activity. We compared the survival of the two different groups ofLeishmaniaduring interaction with human neutrophils, assessing the role of neutrophil extracellular traps. As previously reported, we detected higher nuclease activity in parasites cultured in LP medium. Both LP and HP promastigotes were capable of inducing the release of neutrophil extracellular traps from human neutrophils in a dose- and time-dependent manner. LP parasites had 2.4 times more survival than HP promastigotes. NET disruption was prevented by the treatment of the parasites with ammonium tetrathiomolybdate (TTM), a 3′NT/NU inhibitor. Inhibition of 3′NT/NU by 3′-AMP, 5′-GMP, or TTM decreased promastigote survival upon interaction with neutrophils. Our results show thatLeishmania infantuminduces NET release and that promastigotes can escape NET-mediated killing by 3′-nucleotidase/nuclease activity, thus ascribing a new function to this enzyme.

scholarly journals Taking the Gonococcus-Human Relationship to a Whole New Level: Implications for the Coevolution of Microbes and Humans

mBio ◽  
2011 ◽  
Vol 2 (3) ◽  
Author(s):  
William M. Shafer ◽  
Elizabeth A. Ohneck
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Neisseria Gonorrhoeae ◽  
Bacterial Species ◽  
Human Relationship ◽  
Content Type ◽  
Long Interspersed Nuclear Element

ABSTRACTWhile horizontal gene transfer occurs frequently among bacterial species, evidence for the transfer of DNA from host to microbe is exceptionally rare. However, the recent report by Anderson and Seifert [mBio 2(1):e00005-11, 2011] provides evidence for such an event with the finding that 11% ofNeisseria gonorrhoeaestrains harbor a 685-bp sequence that is 98 to 100% identical to the human long interspersed nuclear element L1. While the function of this element in gonococci remains unclear, this finding significantly impacts our consideration of the coevolution of hosts and microbes, particularly that of humans and pathogens.

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