Project description:Shigella flexneri is historically regarded as the primary agent of bacillary dysentery, yet the closely-related Shigella sonnei is replacing S. flexneri, especially in developing countries. The underlying reasons for this dramatic shift are mostly unknown. Using a zebrafish (Danio rerio) model of Shigella infection, we discover that S. sonnei is more virulent than S. flexneri in vivo. Whole animal dual-RNAseq and testing of bacterial mutants suggest that S. sonnei virulence depends on its O-antigen oligosaccharide (which is unique among Shigella species). We show in vivo using zebrafish and ex vivo using human neutrophils that S. sonnei O-antigen can mediate neutrophil tolerance. Consistent with this, we demonstrate that O-antigen enables S. sonnei to resist phagolysosome acidification and promotes neutrophil cell death. Chemical inhibition or promotion of phagolysosome maturation respectively decreases and increases neutrophil control of S. sonnei and zebrafish survival. Strikingly, larvae primed with a sublethal dose of S. sonnei are protected against a secondary lethal dose of S. sonnei in an O-antigen-dependent manner, indicating that exposure to O-antigen can train the innate immune system against S. sonnei. Collectively, these findings reveal O-antigen as an important therapeutic target against bacillary dysentery, and may explain the rapidly increasing S. sonnei burden in developing countries.
2019-11-19 | GSE140544 | GEO
Project description:Shigella sonnei and S. flexneri isolates in Portugal from 2015 to 2022
Project description:Shigella flexneri 2a and Shigella sonnei were genetically modified to shed large quantities of outer membrane blebs. The blebs, called Generalized Modules for Membrane Antigens (GMMA), were purified and the protein content was estimated using the label-free iBAQ procedure. There were 2308 proteins identified, 660 in GMMA and 2239 in bacteria, of which 288 (GMMA) and 1695 (bacteria) were common to both S. flexneri 2a and S. sonnei. Protein abundances were classified according to the predicted localization. Predicted outer membrane or periplasmic proteins constituted 95.7% and 98.7% of the protein mass of S. flexneri 2a and S. sonnei GMMA, respectively. Among the remaining proteins, small quantities of ribosomal proteins collectively accounted for more than half of the predicted cytoplasmic protein impurities in the GMMA. In GMMA, the outer membrane and periplasmic proteins were enriched 13.3-fold (S. flexneri 2a) and 8.3-fold (S. sonnei) compared to their abundance in the parent bacteria. Both periplasmic and outer membrane proteins were enriched similarly, suggesting that GMMA have a similar surface to volume ratio as the surface to periplasmic volume ratio in these mutant bacteria. Results in S. flexneri 2a and S. sonnei showed high reproducibility indicating a robust GMMA-producing process.
2016-01-12 | PXD002517 | Pride
Project description:Circulation of multidrug-resistant Shigella sonnei and Shigella flexneri among men who have sex with men in Barcelona, Spain, 2015-2019
Project description:Shigella sonnei as an enteric pathogen, can benefit from outcompeting gut commensals such as Escherichia coli and there can be several mechanisms that assist in interbacterial competition. It is, therefore, important to understand these mechanisms as they provide insights into the interactions of these pathogens in the complex environment they exist. We used our novel Bulk Phenotyping of Epidemiological Replicates (BPER) pipeline combined with bacterial Genome Wide Association Studies (GWAS) on a previously described real-world collection of S. sonnei isolates (n=165) to demonstrate the vital role that colicins could have played in shaping the observed epidemiology of S. sonnei. We then used targeted mass spectrometry on representative S. sonnei isolates to detect colicin sequences in cell free supernatants, which further validated our BPER results to suggest the vital role of colicins. Here, we also introduce BPER as an epidemiologically relevant way of phenotypic testing in the laboratory where the phenotypic results can be interpreted with much more relevance to the effects of those phenotypes in natural settings.
Project description:We evaluated the transcriptome changes induced by infection of Hela 229 cells with Shigella flexneri. The sample set consists of a control (mock), total population of infected sample and infected sample sorted into Shigella positive and Shigella negative population.
Project description:"Shigella spp. are the causative agents of shigellosis, which remains a major cause of death in children under the age of five. Shigellosis is marked by fever and leads to hemorrhagic diarrhea; Shigella bacteremia are reported in more severe cases. These clinical features strongly suggest that Shigella survive to plasma exposure, although it has not been previously investigated at a molecular level. In this report, we confirmed in a guinea pig model of shigellosis that local hemorrhages were induced by S. flexneri 5a and S. sonnei and we demonstrated that Shigella reached CD31+/CD34+ blood vessels within the mucosa during late infection stage and further disseminated in the blood circulation. These results confirmed the exposition of Shigella to plasma components during its virulence cycle, from the hemorrhagic colonic mucosa to the blood circulation. We demonstrated that all tested Shigella strains survived to plasma exposure in vitro and we have shown that Serine Protease Autrotransporters of Enterobacteriaceae (SPATEs) are essential for Shigella dissemination within the colonic mucosa and in the blood circulation. We confirmed that SPATEs were expressed and secreted within poorly oxygenated environments encountered by Shigella from hypoxic foci of infection to the blood circulation. We have further demonstrated that SPATEs promoted the survival of Shigella to plasma exposure, by cleaving the complement 3 component (C3), hence impairing the complement system activation."
Project description:In most eukaryotes and bacteria, queuosine (Q) replaces the guanosine at the wobble position of tRNAs harboring a GUN anticodon. To faithfully detect Q-modification in RNAs from Schizosaccharomyces pombe and Shigella flexneri, Q-MaP-Seq was established and applied to tRNAs from S. pombe WT (AEP1) cells and Shigella flexneri WT cells and tgt∆ cells. Q-modification of in vitro-transcribed RNAs and RNAs isolated from S. pombe and S. flexneri followed by reverse transcription using the RT-active DNA polymerase variant RT-KTq I614Y and sequencing of unmodified compared to modified RNAs allowed identification of Q-sites within tRNAs.