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. 2000 May;68(5):2916-24.
doi: 10.1128/IAI.68.5.2916-2924.2000.

VSports注册入口 - Pseudomonas aeruginosa cystic fibrosis isolates induce rapid, type III secretion-dependent, but ExoU-independent, oncosis of macrophages and polymorphonuclear neutrophils

D Dacheux  1 , B Toussaint, M Richard, G Brochier, J Croize, I Attree
Affiliations

Pseudomonas aeruginosa cystic fibrosis isolates induce rapid, type III secretion-dependent, but ExoU-independent, oncosis of macrophages and polymorphonuclear neutrophils (V体育官网)

D Dacheux et al. Infect Immun. 2000 May.

V体育安卓版 - Abstract

Pseudomonas aeruginosa, an opportunistic pathogen responsible most notably for severe infections in cystic fibrosis (CF) patients, utilizes the type III secretion system for eukaryotic cell intoxication. The CF clinical isolate CHA shows toxicity towards human polymorphonuclear neutrophils (PMNs) which is dependent on the type III secretion system but independent of the cytotoxin ExoU. In the present study, the cytotoxicity of this strain toward human and murine macrophages was demonstrated. In low-multiplicity infections (multiplicity of infection, 10), approximately 40% of the cells die within 60 min. Analysis of CHA-infected cells by transmission electron microscopy, DNA fragmentation assay, and Hoechst staining revealed the hallmarks of oncosis: cellular and nuclear swelling, disintegration of the plasma membrane, and absence of DNA fragmentation VSports手机版. A panel of 29 P. aeruginosa CF isolates was screened for type III system genotype, protein secretion profile, and cytotoxicity toward PMNs and macrophages. This study showed that six CF isolates were able to induce rapid ExoU-independent oncosis on phagocyte cells. .

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Figures

FIG. 1
FIG. 1
Cytotoxicity of P. aeruginosa strains CHA, CHA-D1, and CHA-D1(pDD2) toward J774 macrophages (A), B lymphocytes (B), and HeLa cells (C). The percent cytotoxicity was calculated from the release of LDH activity. Data are the means of at least three experiments. (D) J774 macrophages were infected with strain CHA or CHA-D1 (MOI, 10) and examined for morphological alterations by phase-contrast microscopy after 1 h.
FIG. 2
FIG. 2
Growth-phase-dependent cytotoxicity of CHA on J774 macrophages. Bacterial culture was started at 0.1 OD600 unit (●). The percent cytotoxicity was calculated from the release of LDH activity after 1 h (○) and 2 h (◊) of infection. The experiment was repeated twice, and a representative experiment is shown. DO 600nm, optical density at 600 nm.
FIG. 3
FIG. 3
DNA fragmentation assays. (A) DNA was isolated from J774 macrophages or PMNs and migrated on a 1.5% agarose gel. Lanes: 1, ladder molecular size markers; 2, uninfected J774; 3, CHA-infected J774; 4, CHA-D1-infected J774; 5, J774 treated by UV irradiation for 15 min; 6, uninfected PMNs; 7, CHA-infected PMNs; 8, CHA-D1-infected PMNs; 9, PMNs treated with 50 μM actinomycin D for 5 h. (B) Nuclear morphology of PMNs. At 2 h after infection with the CHA strain, cells were stained with the DNA-specific fluorochrome Hoechst 33342. Uninfected cells showed polymorphic nuclei typical for normal PMNs isolated from blood samples. CHA cells exhibited rounded, uniformly stained, swollen nuclei. Apoptotic cells (UV treated) showed typical highly condensed and fragmented nuclei. Observations were done using epifluorescence microscopy (magnification, ×1,000).
FIG. 4
FIG. 4
Electron micrographs of PMNs. (A) Uninfected PMNs as a control. (B) PMNs 1 h after infection with the CHA strain, showing features of oncosis: dispersed chromatin within swollen nucleus, vacuolization, and absence of cell membrane. (C) PMNs 1 h after infection with the CHA-D1 strain. (D) PMNs heated for 30 min at 56°C, showing oncotic cell death morphology with the same profile as in the CHA-infected cells. (E and F) PMNs, treated with actinomycin D, showing either early apoptotic morphology with intense perinuclear chromatin aggregation but cytoplasm integrity (E) or late apoptotic morphology characterized by degenerated nuclei, where the chromatin is completely aggregated as in early apoptosis, but dissolution of the cytoplasm (F). The arrow indicates bacteria. Bars, 1 μm.
FIG. 5
FIG. 5
Electron micrographs of J774 cells. (A) Uninfected J774 cells as a control. (B) J774 cells 1 h after infection with CHA, showing oncotic morphology: flocculation of the chromatin, dissolution of the cytoplasm, and swollen nuclei. (C) J774 cells 1 h after infection with the CHA-D1 strain. (D and E) J774 cells treated by UV-irradiation showing either early apoptotic morphology with intense perinuclear chromatin aggregation but cytoplasm integrity (D) or late apoptotic morphology with the nucleus having the same profile as in early apoptosis but dissolution of the cytoplasm (E). The arrow indicates bacteria. Bars, 2 μm.
FIG. 6
FIG. 6
Distribution of the exsA and exoU genotypes, in vitro type III secretion ability, and cytotoxicity to PMNs of 29 P. aeruginosa CF isolates. (A) Percent cytotoxicity calculated from the release of LDH activity. (B) In vitro induction of the type III secretion system, measured by SDS-PAGE analysis of culture supernatants. (C) Southern blot analysis of chromosomal DNAs after digestion with EcoRI. The restriction fragment length polymorphism encountered in exoU-containing strains (CF16, CF17, and CF18) is shown. Molecular sizes markers are indicated on the right.
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References

    1. Coburn J, Frank D W. Macrophages and epithelial cells respond differently to the Pseudomonas aeruginosa type III secretion system. Infect Immun. 1999;67:3151–3154. - "V体育2025版" PMC - PubMed
    1. Cornelis G R, Boland A, Boyd A P, Geuijen C, Iriarte M, Neyt C, Sory M P, Stainier I. The virulence plasmid of Yersinia, an antihost genome. Microbiol Mol Biol Rev. 1998;62:1315–1352. - "V体育ios版" PMC - PubMed
    1. Dacheux D, Attree I, Schneider C, Toussaint B. Cell death of human polymorphonuclear neutrophils induced by a Pseudomonas aeruginosa cystic fibrosis isolate requires a functional type III secretion system. Infect Immun. 1999;67:6164–6167. - PMC - PubMed
    1. Elborn J S, Shale D J. Lung injury in cystic fibrosis. Thorax. 1990;45:970–973. - PMC - PubMed
    1. Fernandez-Prada C, Tall B D, Elliott S E, Hoover D L, Nataro J P, Venkatesan M M. Hemolysin-positive enteroaggregative and cell-detaching Escherichia coli strains cause oncosis of human monocyte-derived macrophages and apoptosis of murine J774 cells. Infect Immun. 1998;66:3918–3924. - PMC (VSports注册入口) - PubMed

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