Gonococcal Cervicitis: A Role for Biofilm in Pathogenesis

Steichen, Christopher T.; Shao, Jun Peng; Ketterer, Margaret R.; Apicella, Michael A.

doi:10.1086/593336

Cited by 71 publications

(111 citation statements)

References 19 publications

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“…A number of microscopy studies have explored the ultrastructure of the N. gonorrhoeae-infected epithelial cell 3D ultrastructure of N. gonorrhoeae infection cortex and the bacterial microcolony (Edwards et al, 2000;Evans, 1977;McGee et al, 1983;Steichen et al, 2008;Stephens, 1989;Swanson, 1983;Ward & Watt, 1972). GC are often seen to attach as microcolonies and to induce dramatic alterations to host cell microvilli, particularly at the microcolony periphery.…”

Section: Discussionmentioning

confidence: 99%

Influence of type IV pilus retraction on the architecture of the Neisseria gonorrhoeae-infected cell cortex

et al. 2009

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Early in infection, Neisseria gonorrhoeae can be observed to attach to the epithelial cell surface as microcolonies and induce dramatic changes to the host cell cortex. We tested the hypothesis that type IV pili (Tfp) retraction plays a role in the ultrastructure of both the host cell cortex and the bacterial microcolony. Using serial ultrathin sectioning, transmission electron microscopy and 3D reconstruction of serial 2D images, we have obtained what we believe to be the first 3D reconstructions of the N. gonorrhoeae-host cell interface, and determined the architecture of infected cell microvilli as well as the attached microcolony. Tfp connect both wild-type (wt) and Tfp retraction-deficient bacteria with each other, and with the host cell membrane. Tfp fibres and microvilli form a lattice in the wt microcolony and at its periphery. Wt microcolonies induce microvilli formation and increases of surface area, leading to an approximately ninefold increase in the surface area of the host cell membrane at the site of attachment. In contrast, Tfp retractiondeficient microcolonies do not affect these parameters. Wt microcolonies had a symmetrical, dome-shaped structure with a circular 'footprint', while Tfp retraction-deficient microcolonies were notably less symmetrical. These findings support a major role for Tfp retraction in microvilli and microcolony architecture. They are consistent with the biophysical attributes of Tfp and the effects of Tfp retraction on epithelial cell signalling. INTRODUCTIONNeisseria gonorrhoeae (the gonococcus, or GC) remains a significant public health concern. The Gram-negative diplococcus causes a million cases of gonorrhoea annually in Western Europe and North America, and over 62 million cases worldwide (World Health Organization). Humans are the only known reservoir for GC. The exquisite tropism of GC for man and the ability of GC to establish a carrier state (Turner et al., 2002) reflect a highly evolved relationship between pathogen and host.Gonococcal attachment is promoted by type IV pili (Tfp), peritrichous fibres that are 6 nm in width and up to several micrometres in length. The Tfp filament is composed of helical polymers of pilin subunits (Craig et al., 2006;Parge et al., 1995) and minor proteins (Carbonnelle et al., 2005;Winther-Larsen et al., 2005). Tfp participate in important biological processes such as DNA uptake/genetic exchange, twitching motility, attachment, and host cell signalling (Mattick, 2002;. These activities require, or are enhanced by, the retraction of Tfp fibres (Wolfgang et al., 2000).Gonococcal Tfp retraction is an activity that requires PilT, the Tfp retraction motor subunit (Wolfgang et al., 1998). Retracting Tfp generate strong 'pull' forces, ranging from 50 picoNewtons (pN) to 1 nanoNewton (nN) (Biais et al., 2008;Opitz et al., 2009). Repeated cycles of Tfp extension, substrate attachment and Tfp retraction allow GC to crawl over surfaces and aggregate into microcolonies. Tfp retraction from bacteria in a microcolony allows the community to craw...

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Section: Discussionmentioning

confidence: 99%

Influence of type IV pilus retraction on the architecture of the Neisseria gonorrhoeae-infected cell cortex

et al. 2009

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“…The Ng-ntrX mutant was complemented in cis by double crossover of a wild-type (WT) copy of the ntrYX locus into the proB locus in the gonococcal chromosome using the complementation construct pCTS32 (30). The entire ntrYX locus, including 300-bp upstream and downstream flanking regions, was amplified from N. gonorrhoeae 1291 wild-type genomic DNA using primers COMP-F (5=-TACAAACTAAGTTTCCAT CCG-3=) and COMP-R (5=-AAAGCGCGTTTTTCCGCAT-3=).…”

Section: Methodsmentioning

confidence: 99%

Characterization of an ntrX Mutant of Neisseria gonorrhoeae Reveals a Response Regulator That Controls Expression of Respiratory Enzymes in Oxidase-Positive Proteobacteria

et al. 2013

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e NtrYX is a sensor-histidine kinase/response regulator two-component system that has had limited characterization in a small number of Alphaproteobacteria. Phylogenetic analysis of the response regulator NtrX showed that this two-component system is extensively distributed across the bacterial domain, and it is present in a variety of Betaproteobacteria, including the human pathogen Neisseria gonorrhoeae. Microarray analysis revealed that the expression of several components of the respiratory chain was reduced in an N. gonorrhoeae ntrX mutant compared to that in the isogenic wild-type (WT) strain 1291. These included the cytochrome c oxidase subunit (ccoP), nitrite reductase (aniA), and nitric oxide reductase (norB). Enzyme activity assays showed decreased cytochrome oxidase and nitrite reductase activities in the ntrX mutant, consistent with microarray data. N. gonorrhoeae ntrX mutants had reduced capacity to survive inside primary cervical cells compared to the wild type, and although they retained the ability to form a biofilm, they exhibited reduced survival within the biofilm compared to wild-type cells, as indicated by LIVE/DEAD staining. Analyses of an ntrX mutant in a representative alphaproteobacterium, Rhodobacter capsulatus, showed that cytochrome oxidase activity was also reduced compared to that in the wild-type strain SB1003. Taken together, these data provide evidence that the NtrYX two-component system may be a key regulator in the expression of respiratory enzymes and, in particular, cytochrome c oxidase, across a wide range of proteobacteria, including a variety of bacterial pathogens.

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“…The phenotype of a Neisseria gonorrhoeae strain with disrupted msbB has also been examined (14)(15)(16). Lipid A from the LOS of these mutant bacteria is penta-acylated (14).…”

Section: Ipopolysaccharide (Lps) Is An Importance Virulence Factor Inmentioning

confidence: 99%

Hexa-Acylated Lipid A Is Required for Host Inflammatory Response to Neisseria gonorrhoeae in Experimental Gonorrhea

et al. 2014

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e Neisseria gonorrhoeae causes gonorrhea, a sexually transmitted infection characterized by inflammation of the cervix or urethra. However, a significant subset of patients with N. gonorrhoeae remain asymptomatic, without evidence of localized inflammation. Inflammatory responses to N. gonorrhoeae are generated by host innate immune recognition of N. gonorrhoeae by several innate immune signaling pathways, including lipooligosaccharide (LOS) and other pathogen-derived molecules through activation of innate immune signaling systems, including toll-like receptor 4 (TLR4) and the interleukin-1␤ (IL-1␤) processing complex known as the inflammasome. The lipooligosaccharide of N. gonorrhoeae has a hexa-acylated lipid A. N. gonorrhoeae strains that carry an inactivated msbB (also known as lpxL1) gene produce a penta-acylated lipid A and exhibit reduced biofilm formation, survival in epithelial cells, and induction of epithelial cell inflammatory signaling. We now show that msbB-deficient N. gonorrhoeae induces less inflammatory signaling in human monocytic cell lines and murine macrophages than the parent organism. The penta-acylated LOS exhibits reduced toll-like receptor 4 signaling but does not affect N. gonorrhoeae-mediated activation of the inflammasome. We demonstrate that N. gonorrhoeae msbB is dispensable for initiating and maintaining infection in a murine model of gonorrhea. Interestingly, infection with msbB-deficient N. gonorrhoeae is associated with less localized inflammation. Combined, these data suggest that TLR4-mediated recognition of N. gonorrhoeae LOS plays an important role in the pathogenesis of symptomatic gonorrhea infection and that alterations in lipid A biosynthesis may play a role in determining symptomatic and asymptomatic infections. L ipopolysaccharide (LPS) is an importance virulence factor in Gram-negative bacteria. LPS consists of a complex polysaccharide attached to a core saccharide consisting of 3-deoxy-Dmannooctulosonic acid (keto-deoxyoctulosonate [KDO]) and an acylated diglucosamine moiety known as lipid A. Neisseria species (as well as some other commensal and pathogenic bacteria) make LPS with a truncated polysaccharide structure, which is termed lipooligosaccharide (LOS). LOS is a potent mediator of inflammatory signaling and is known to activate several host innate immune signaling systems, including toll-like receptor 4 (TLR4) through the lipid A molecule, C-lectin receptors (particularly MGL and DC-SIGN) through the oligosaccharide structure, and the caspase-1 activating complex known as the NLRP3-inflammasome through mechanisms yet to be determined (1-4).Lipid A synthesis is largely carried out by a highly conserved set of enzymatic steps that include the acylation of glucosaminebased precursors followed by condensation of these acylated glucosamine structures into the tetra-acylated disaccharide backbone that is the core structure of lipid A. This core is further decorated by the addition of two KDOs (2) and a variety of other additional modifications of the lipidated dis...

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Gonococcal Cervicitis: A Role for Biofilm in Pathogenesis

Cited by 71 publications

References 19 publications

Influence of type IV pilus retraction on the architecture of the Neisseria gonorrhoeae-infected cell cortex

Influence of type IV pilus retraction on the architecture of the Neisseria gonorrhoeae-infected cell cortex

Characterization of an ntrX Mutant of Neisseria gonorrhoeae Reveals a Response Regulator That Controls Expression of Respiratory Enzymes in Oxidase-Positive Proteobacteria

Hexa-Acylated Lipid A Is Required for Host Inflammatory Response to Neisseria gonorrhoeae in Experimental Gonorrhea

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