The phase-variable pilus-associated protein PilC is commonly expressed in clinical isolates of Neisseria gonorrhoeae, and shows sequence variability among strains

Bäckman, M.; Källström, Helena; Jonsson, Ann‐Beth

doi:10.1099/00221287-144-1-149

Cited by 12 publications

(6 citation statements)

References 30 publications

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“…Unlike their Neisseria counterparts, K. kingae PilC1 and PilC2 have very low levels of homology to each other (1,18). Loss of either PilC1 or PilC2 from K. kingae resulted in a decrease in adherence, a result that is consistent with findings for pathogenic Neisseria strains, suggesting that the PilC proteins function as adhesins (2,14,17,21).…”

Section: Discussionsupporting

confidence: 77%

Kingella kingae Expresses Type IV Pili That Mediate Adherence to Respiratory Epithelial and Synovial Cells

Kehl-Fie

Miller

Geme³

2008

J Bacteriol

107

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Kingella kingae is a gram-negative bacterium that colonizes the respiratory tract and is a common cause of septic arthritis and osteomyelitis. Despite the increasing frequency of K. kingae disease, little is known about the mechanism by which this organism adheres to respiratory epithelium and seeds joints and bones. Previous work showed that K. kingae expresses long surface fibers that vary in surface density. In the current study, we found that these fibers are type IV pili and are necessary for efficient adherence to respiratory epithelial and synovial cells and that the number of pili expressed by the bacterium correlates with the level of adherence to synovial cells but not with the level of adherence to respiratory cells. In addition, we established that the major pilin subunit is encoded by a pilA homolog in a conserved region of the chromosome that also contains a second pilin gene and a type IV pilus accessory gene, both of which are dispensable for pilus assembly and pilusmediated adherence. Upon examination of the K. kingae genome, we identified two genes in physically separate locations on the chromosome that encode homologs of the Neisseria PilC proteins and that have only a low level homology to each other. Examination of mutant strains revealed that both of the K. kingae PilC homologs are essential for a wild-type level of adherence to both respiratory epithelial and synovial cells. Taken together, these results demonstrate that type IV pili and the two PilC homologs play important roles in mediating K. kingae adherence.

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Section: Discussionsupporting

confidence: 77%

Kingella kingae Expresses Type IV Pili That Mediate Adherence to Respiratory Epithelial and Synovial Cells

Kehl-Fie

Miller

Geme³

2008

J Bacteriol

107

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“…PYKK081 OMVs were shown to contain PilC2, an adhesin with similarity to PilC2 found in the pathogenic Neisseria species [50, 51]. Previous work demonstrated that type IV pili and the two PilC2 homologs play important roles in mediating K. kingae adherence [17].…”

Section: Discussionmentioning

confidence: 99%

Cytotoxic effects of Kingella kingae outer membrane vesicles on human cells

Maldonado

Wei

Kachlany

et al. 2011

Microbial Pathogenesis

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Kingella kingae is an emerging pathogen causing osteoarticular infections in pediatric patients. Electron microscopy of K. kingae clinical isolates revealed the heterogeneously-sized membranous structures blebbing from the outer membrane that were classified as outer membrane vesicles (OMVs). OMVs purified from the secreted fraction of a septic arthritis K. kingae isolate were characterized. Among several major proteins, K. kingae OMVs contained virulence factors RtxA toxin and PilC2 pilus adhesin. RtxA was also found secreted as a soluble protein in the extracellular environment indicating that the bacterium may utilize different mechanisms for the toxin delivery. OMVs were shown to be hemolytic and possess some leukotoxic activity while high leukotoxicity was detected in the non-hemolytic OMV-free component of the secreted fraction. OMVs were internalized by human osteoblasts and synovial cells. Upon interaction with OMVs, the cells produced increased levels of human granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleuskin 6 (IL-6) suggesting that these cytokines might be involved in the signaling response of infected joint and bone tissues during natural K. kingae infection. This study is the first report of OMV production by K. kingae and demonstrates that OMVs are a complex virulence factor of the organism causing cytolytic and inflammatory effects on host cells.

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“…Pili are inhibitory to phagocytosis of gonococci by polymorphonuclear cells (18,22,48), but their effect on internalization by epithelial cells is unclear. Pili are composed of PilE, the major pilus subunit; PilC, an adherence-associated protein; and possibly other components (1,54,55). Gonococci undergo pilus phase variation, converting from pilus positive (P ϩ ) to P Ϫ and from P Ϫ to P ϩ in vitro and quite probably in vivo as well (67,68).…”

mentioning

confidence: 99%

Neisseria gonorrhoeae Coordinately Uses Pili and Opa To Activate HEC-1-B Cell Microvilli, Which Causes Engulfment of the Gonococci

et al. 1999

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This study was undertaken to examine concomitant roles of pili and colony opacity-associated proteins (Opa) in promoting Neisseria gonorrhoeae adherence to and invasion of human endometrial HEC-1-B cells. Adherence of N. gonorrhoeae to cultured HEC-1-B cells was saturable, even though organisms adhered to <50% of the cells. During 4 to 6 h of incubation, adherent mono- and diplococci formed microcolonies on the surfaces of the cells. Microvilli of the HEC-1-B cells adhered by their distal ends to individual cocci within the microcolonies. When the microcolonies grew from isogenic pilus-negative (P−) Opa−, P− Opa+, or P+ Opa−gonococci, microvilli did not elongate, and the colonies were not engulfed. In contrast, the microvilli markedly elongated during exposure to P+ Opa+ gonococci. The microvilli adhered to the organisms along their full lengths and appeared to actively participate in the engulfment of the microcolonies. Internalized microcolonies, with P+ Opa+gonococci, contained dividing cocci and appeared to be surrounded by cell membrane but were not clearly within vacuoles. In contrast, degenerate individual organisms were within vacuoles. Low doses of chloramphenicol, which inhibits protein synthesis by both prokaryotes and eukaryotes, prevented the microvillar response to and internalization of the P+ Opa+ gonococci; higher doses caused internalization without microvillus activation. Cycloheximide and anisomycin, which inhibit only eukaryotic protein synthesis, caused dose-dependent enhancement of uptake. Cytochalasins reduced engulfment; colchicine had no effect. These results show that gonococci must express both pili and Opa to be engulfed efficiently by HEC-1-B cells.

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The phase-variable pilus-associated protein PilC is commonly expressed in clinical isolates of Neisseria gonorrhoeae, and shows sequence variability among strains

Cited by 12 publications

References 30 publications

Kingella kingae Expresses Type IV Pili That Mediate Adherence to Respiratory Epithelial and Synovial Cells

Kingella kingae Expresses Type IV Pili That Mediate Adherence to Respiratory Epithelial and Synovial Cells

Cytotoxic effects of Kingella kingae outer membrane vesicles on human cells

Neisseria gonorrhoeae Coordinately Uses Pili and Opa To Activate HEC-1-B Cell Microvilli, Which Causes Engulfment of the Gonococci

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