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ABSTRACT:
PROVIDER: PRJNA1260753 | ENA |
REPOSITORIES: ENA
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Project description:The Staphylococcus aureus Panton Valentine leukocidin (PVL) is a pore-forming toxin secreted by strains epidemiologically associated with the current outbreak of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and with the often lethal necrotizing pneumonia. To investigate the role of PVL in pulmonary disease, we tested the pathogenicity of clinical isolates, isogenic PVL-negative and PVL-positive S. aureus strains, as well as purified PVL, in a mouse acute pneumonia model. Here we show that PVL is sufficient to cause pneumonia and that the expression of this leukotoxin induces global changes in transcriptional levels of genes encoding secreted and cell-wall-anchored staphylococcal proteins, including the lung inflammatory factor staphylococcal protein A (Spa). Keywords: comparative transcription profile in the presence or absence of PVL toxin
2007-02-13 | GSE6985 | GEO
Project description:Panton-Valentine Leukocidin (PVL) is a Staphylococcus aureus toxin that binds to and kills human neutrophils resulting in the formation of neutrophil extracellular traps. A subset of individuals colonized with PVL expressing S. aureus suffer from recurring infections. We found that neutrophils from affected individuals display increased spontaneous NET formation after isolation, and increased sensitivity to killing by PVL. Compared to healthy controls, the expression of the target receptors for PVL, CD45 and C5L2, but not CD88, was increased in these patients, and the expression correlated to the amount of PVL-induced NETs produced. NADPH-oxidase activity was not important for PVL induced NETosis as neutrophils from CGD patients produced NETs in response to PVL. Through NET proteome analysis we identified that the protein content of PVL induced NETs is different from mitogen induced NETs. The abundance of the antimicrobial proteins LL37, myeloperoxidase, azurocidin, and proteinase 3 was lower on PVL NETs and PVL-induced NETs were deficient in killing Staphylococcus aureus. Neutrophils from patients that suffer from recurring PVL-positive infections may be more sensitive to PVL-induced NETosis, impairing their ability to combat the infection.
2023-11-23 | PXD025702 | Pride
Project description:Staphylococcus aureus is a Gram-positive human pathogen causing a variety of human diseases in both hospital and community settings. This bacterium is so closely associated with prophages that it is rare to find S. aureus isolates without prophages. Two phages are known to be important for staphylococcal virulence: the beta-hemolysin (hlb) converting phage and the Panton-Valentine Leukocidin (PVL) converting phage. The hlb-converting phage is found in more than 90% of clinical isolates of S. aureus. This phage produces exotoxins and immune modulatory molecules, which inhibit human innate immune responses. The PVL-converting phage produces the two-component exotoxin PVL, which can kill human leucocytes. This phage is wide-spread among community-associated methicillin resistant S. aureus (CA-MRSA). It also shows strong association with soft tissue infections and necrotizing pneumonia. Several lines of evidence suggest that staphylococcal prophages increase bacterial virulence not only by providing virulence factors but also by altering bacterial gene expression: 1) Transposon insertion into prophage regulatory genes, but not into the genes of virulence factors, reduced S. aureus killing of Caenorhabditis elegans.; 2) Although the toxins and immune modulatory molecules encoded by the hlb- converting phages do not function in the murine system, deletion of ϕNM3, the hlb-converting phage in S. aureus Newman, reduced staphylococcal virulence in the murine abscess formation model. 3) In a preliminary microarray experiment, prophages in S. aureus Newman altered the expression of more than 300 genes. In this research proposal, using microarray and high-throughput quantitative RT-PCR (qRT-PCR) technologies, we will identify the effects of the two important staphylococcal phages on the gene expression of S. aureus in both in vitro and in vivo conditions. This project is intended to be completed within one year. All the data – microarray, qRT-PCR and all the primer sequences- will be made available to public 6 month after completion. Data from this project will help us to understand the role of prophages in the S. aureus pathogenesis and can lead to development of a strategy to interfere with the pathogenesis process. Following strains were grown in TSA broth: Staphylococcus aureus USA300 (reference) Staphylococcus aureus USA300 with deletion of ϕSa2usa (Query) Staphylococcus aureus USA300 with deletion of ϕSa3usa (Query) Staphylococcus aureus USA300 Prophage-free mutant (Query) Staphylococcus aureus USA300 Prophage-free mutant lysogenized with ϕSa2mw (Query) Staphylococcus aureus USA300 Prophage-free mutant lysogenized with ϕSa3usa (Query) strain: Staphylococcus aureus USA300 Prophage-free mutant lysogenized with both ϕSa2mw and ϕSa3usa (Query) RNA samples were harvested at early log, midlog and stationary phase.Samples were hybridized on aminosilane coated slides with 70-mer oligos.
2011-02-28 | E-GEOD-26623 | biostudies-arrayexpress
Project description:Staphylococcus aureus is a Gram-positive human pathogen causing a variety of human diseases in both hospital and community settings. This bacterium is so closely associated with prophages that it is rare to find S. aureus isolates without prophages. Two phages are known to be important for staphylococcal virulence: the beta-hemolysin (hlb) converting phage and the Panton-Valentine Leukocidin (PVL) converting phage. The hlb-converting phage is found in more than 90% of clinical isolates of S. aureus. This phage produces exotoxins and immune modulatory molecules, which inhibit human innate immune responses. The PVL-converting phage produces the two-component exotoxin PVL, which can kill human leucocytes. This phage is wide-spread among community-associated methicillin resistant S. aureus (CA-MRSA). It also shows strong association with soft tissue infections and necrotizing pneumonia. Several lines of evidence suggest that staphylococcal prophages increase bacterial virulence not only by providing virulence factors but also by altering bacterial gene expression: 1) Transposon insertion into prophage regulatory genes, but not into the genes of virulence factors, reduced S. aureus killing of Caenorhabditis elegans.; 2) Although the toxins and immune modulatory molecules encoded by the hlb- converting phages do not function in the murine system, deletion of NM3, the hlb-converting phage in S. aureus Newman, reduced staphylococcal virulence in the murine abscess formation model. 3) In a preliminary microarray experiment, prophages in S. aureus Newman altered the expression of more than 300 genes. In this research proposal, using microarray and high-throughput quantitative RT-PCR (qRT-PCR) technologies, we will identify the effects of the two important staphylococcal phages on the gene expression of S. aureus in both in vitro and in vivo conditions. This project is intended to be completed within one year. All the data – microarray, qRT-PCR and all the primer sequences- will be made available to public 6 month after completion. Data from this project will help us to understand the role of prophages in the S. aureus pathogenesis and can lead to development of a strategy to interfere with the pathogenesis process. Staphylococcus aureus subsp.aureus strain Newman (reference) and Staphylococcus aureus subsp.aureus strain Newman yhcR knockout(query) were grown in TSA broth.Samples were grown under aerobic and anaerobic conditions and RNA samples harvested at mid log, stationary, and log phases.Samples were hybridized on aminosilane coated slides with 70-mer oligos.
2011-12-31 | E-GEOD-26585 | biostudies-arrayexpress
Project description:The role of Panton‐Valentine leukocidin (PVL) in Staphylococcus aureus pathogenesis is controversial. Here, we show that an unintended point mutation in the agr P2 promoter of S.aureus caused the phenotypes in gene regulation and murine pneumonia attributed to PVL by Labandeira‐Rey et al. (Science 315:1130‐3, 2007). In agreement with previous studies that failed to detect similar effects of PVL using community‐associated methicillin‐resistant S. aureus strains, we found no significant impact of PVL on gene expression or pathogenesis after we repaired the mutation. These findings further contribute to the idea that PVL does not have a major impact on S. aureus pathogenesis and resolve debate about its role in murine infection models. Moreover, our results demonstrate that a single nucleotide polymorphism in an intergenic region can dramatically impact bacterial physiology and virulence. Finally, our work emphasizes the need to frequently evaluate the integrity of the S. aureus agr locus.
2009-12-31 | GSE14394 | GEO
Project description:The role of Pantonâ??Valentine leukocidin (PVL) in Staphylococcus aureus pathogenesis is controversial. Here, we show that an unintended point mutation in the agr P2 promoter of S.aureus caused the phenotypes in gene regulation and murine pneumonia attributed to PVL by Labandeiraâ??Rey et al. (Science 315:1130â??3, 2007). In agreement with previous studies that failed to detect similar effects of PVL using communityâ??associated methicillinâ??resistant S. aureus strains, we found no significant impact of PVL on gene expression or pathogenesis after we repaired the mutation. These findings further contribute to the idea that PVL does not have a major impact on S. aureus pathogenesis and resolve debate about its role in murine infection models. Moreover, our results demonstrate that a single nucleotide polymorphism in an intergenic region can dramatically impact bacterial physiology and virulence. Finally, our work emphasizes the need to frequently evaluate the integrity of the S. aureus agr locus. 7 hour growth, with 5 different strain comparisons
2010-05-16 | E-GEOD-14394 | biostudies-arrayexpress
Project description:To study the effect of Radix Paeoniae Rubra decoction on tolerance of Staphylococcus aureus.The effect of Radix Paeoniae Rubra on the resistance of Staphylococcus aureus to oxacillin sodium was studied by millipore dilution method in this experiment.At the same time ,conducted on transcriptome analysis of Staphylococcus aureus related genes in Radix Paeoniae Rubra.And to detect the expression level of related genes of Staphylococcus aureus under the action of Radix Paeoniae Rubra by PCR technology.The tolerance of Staphylococcus aureus was decreased obviously when the concentration of Radix Paeoniae Rubra decoction was above 1mg/ml.The effect of Radix Paeoniae Rubra decoction on the expression of tolerance genes femB,pvL and gluM when the concentration of Radix Paeoniae Rubra decoction was above 4mg/ml.When rhe concentration of Radix Paeoniae Rubra is more than 1mg/ml,it can effectively reduce the resistance of Staphylococcus aureus to oxacillin sodium.The reason may be due to the effect of Radix Paeoniae Rubra on the resistance gene of Staphylococcus aureus.
2021-01-30 | GSE165791 | GEO
Project description:The pathogen Staphylococcus aureus can invade and survive within human cells. There, the intracellular bacterium induces host cell death, which may facilitate spread of infection and tissue destruction. We here conducted a shRNA screen and infected the library of knock-down cells with S. aureus. We identified calcium signaling pathways to play a role in S. aureus invasion and cytotoxicity. For latter, the intracellular bacteria induce a cytoplasmic and mitochondrial Ca2+-overload, which results in host cell death.
2021-10-31 | GSE156073 | GEO
Project description:Panton-valentine leukocidin (PVL) has been linked to worldwide emergence of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) -- its role in virulence in unclear. Here we show that PVL had no effect on global gene expression of prominent CA-MRSA strains nor did it affect bacterial clearance from lungs, spleen and kidneys in a highly discriminatory rabbit bacteremia model. These findings negate a large body of epidemiological research that implicated PVL in CA-MRSA virulence. Keywords: mutant vs wild type in 2 different growth phases grown in 2 different medias
2008-09-12 | GSE8677 | GEO