Pneumococcal BgaA promotes host organ bleeding and coagulation in mouse sepsis model
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE190418 | GEO | 2022/07/18
REPOSITORIES: GEO
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Project description:Background Mortality from bacterial meningitis, predominately caused by Streptococcus pneumoniae, exceeds 50% in low and middle income countries in sub-Saharan Africa with high HIV prevalence. Underlying causes of high mortality are poorly understood. We examined the host and pathogen proteome in adults with proven pneumococcal meningitis (PM), testing if differentially expressed proteins in CSF were implicated in outcome. Materials/methods CSF proteomes were analysed by quantitative Mass-Spectrometry. Spectra were identified using the Swissprot human and TIGR4 pneumococcal protein libraries. Proteins were quantitated and analysed against clinical outcome. Unique proteins in PM were identified against published normal CSF proteome. Random-Forest models were used to test for protein signatures discriminating outcome. Proteins of interest were tested for their effects on growth and opsonophagocytic killing of S. pneumoniae. Results CSF proteomes were available for 57 Adults with PM (median age 32 years, 60% male, 70% HIV-1 co-infected, mortality 63%). 360 individual human and 23 pneumococcal proteins were identified. Of the human protein hits, 30% were not expressed in normal CSF, and these were strongly associated with inflammation and primarily related to neutrophil activity. No human protein signature predicted outcome. However, expression of the essential S. pneumoniae protein Elongation Factor Tu (EF-Tu) was significantly increased in CSF of non-survivors (False Discovery Rate (q) <0.001). Expression of EF-Tu was negatively co-correlated against expression of Neutrophil defensin (r 0.4 p p<0.002), but not against complement proteins C3 or Factor H. In vitro, addition of EF-Tu protein impaired S. pneumoniae neutrophil killing when osponised with CSF. Conclusions Excessive CSF levels of S. pneumoniae EF-Tu protein was associated with reduced survival in human meningitis. Preliminary studies show EF-Tu inhibits neutrophil mediated killing of S. pneumoniae in CSF. Further functional studies are required to better understand the mechanistic role of EF-Tu during PM.
2020-11-09 | PXD021268 | Pride
Project description:Escherichia coli and Staphylococcus are among the most common causes of bacterial sepsis, a deadly syndrome characterized by uncontrolled activation of coagulation and complement enzymatic cascades an exaggerated immune response. We performed in vivo experimental sepsis in baboons to characterize the host response to bacterial infection in blood cells. We demonstrate that bacterial infection leads to early induction of proinflammatory genes followed by a delayed activation of anti-inflammatory pathways. In addition, we observe changes in genes and pathways associated coagulation and complement as well as with leukocyte adhesion, migration and cell death. Our study provides important insights into the temporal kinetics of gene expression in leukocytes during bacterial sepsis.
2023-06-12 | GSE221652 | GEO
Project description:Influenza A virus (IAV) predisposes individuals to secondary infections with the bacterium Streptococcus pneumoniae (the pneumococcus). Infections may manifest as pneumonia, sepsis, meningitis or otitis media (OM). It remains controversial as to whether secondary pneumococcal disease is due to the induction of an aberrant immune response or IAV induced immunosuppression. Moreover, as the majority of studies have been performed in the context of pneumococcal pneumonia, it remains unclear how far these findings can be extrapolated to other pneumococcal disease phenotypes. Here, we demonstrate that the viral hemagglutinin (HA) mediates bacterial OM by inducing a pro-inflammatory response in the middle ear cavity in a replication-dependent manner. Importantly, our findings show that it is the inflammatory response that mediates pneumococcal replication; not viral suppression of the immune system or epithelial damage. This study provide the first evidence that HA induced inflammation drives pneumococcal replication in the middle ear cavity, which has important consequences to the treatment of pneumococcal OM.
2013-01-01 | GSE41098 | GEO
Project description:Pneumococcal pneumonia is a leading cause of death and a major source of human morbidity. The initial immune response plays a central role in determining the course and outcome of pneumococcal disease. We combine bacterial titer measurements from mice infected with Streptococcus pneumoniae with mathematical modeling to investigate the coordination of immune responses and the effects of initial inoculum on outcome. To evaluate the contributions of individual components, we systematically build a mathematical model from three subsystems that describe the succession of defensive cells in the lung: resident alveolar macrophages, neutrophils and monocyte-derived macrophages. The alveolar macrophage response, which can be modeled by a single differential equation, can by itself rapidly clear small initial numbers of pneumococci. Extending the model to include the neutrophil response required additional equations for recruitment cytokines and host cell status and damage. With these dynamics, two outcomes can be predicted: bacterial clearance or sustained bacterial growth. Finally, a model including monocyte-derived macrophage recruitment by neutrophils suggests that sustained bacterial growth is possible even in their presence. Our model quantifies the contributions of cytotoxicity and immune-mediated damage in pneumococcal pathogenesis.
2020-03-26 | BIOMD0000000924 | BioModels
Project description:Treatment of pneumococcal infections is limited by antibiotic resistance and exacerbation of disease by bacterial lysis releasing pneumolysin toxin and other inflammatory factors. We identified a novel peptide in the Klebsiella pneumoniae secretome, which enters Streptococcus pneumoniae via its AmiA-AliA/AliB permease. Subsequent downregulation of genes for amino acid biosynthesis and peptide uptake was associated with reduction of pneumococcal growth in defined medium and human cerebrospinal fluid, irregular cell shape, decreased chain length and decreased genetic transformation. The bacteriostatic effect was specific to S. pneumoniae and Streptococcus pseudopneumoniae with no effect on Streptococcus mitis, Haemophilus influenzae, Staphylococcus aureus or K. pneumoniae. Peptide sequence and length were crucial to growth suppression. The peptide reduced pneumococcal adherence to primary human airway epithelial cell cultures and colonization of rat nasopharynx, without toxicity. We also analysed the effect of peptide on the proteome of S. pneumoniae. We found alteration of the proteome by the peptide with some proteins turned on or off in line with the transcriptomic changes. We therefore identified a peptide with potential as a therapeutic for pneumococcal diseases suppressing growth of multiple clinical isolates, including antibiotic resistant strains, while avoiding bacterial lysis and dysbiosis.
2024-04-08 | PXD050408 | Pride
Project description:The primary mechanism by which pneumococcal capsular polysaccharide-based vaccines are believed to mediate protection is by induction of serotype-specific opsonic antibodies that facilitate bacterial killing by phagocytes (opsonophagocytosis). However, antibodies that are protective against experimental pneumococcal pneumonia in mice but do not promote opsonophagocytic killing in vitro have also been identified 1-3. Such non-opsonic antibodies are associated with bacterial clearance in vivo, but the mechanism by which this occurs is unknown. In this letter, we demonstrate that a protective, non-opsonic serotype 3 pneumococcal capsular polysaccharide-specific monoclonal antibody (MAb) enhances quorum sensing, which results in competence induction and fratricide of serotype 3 pneumococcus. Gene expression profile analysis revealed that the MAb together with the pneumococcal autoinducer, competence stimulating peptide 2 (CSP2), augments differential expression of competence (com) related bacteriocin-like peptide (blp) genes that are known to be involved in pneumococcal fratricide. Taken together, these findings reveal a previously unsuspected mechanism of antibody action, namely, enhancement of quorum sensing and bacterial fratricide. Given that this activity does not require phagocytes, antibodies that function accordingly may hold promise as adjuncts to current vaccines or as desired products of next generation pneumococcal vaccines. 6 samples
2011-03-01 | E-GEOD-27258 | biostudies-arrayexpress
Project description:The primary mechanism by which pneumococcal capsular polysaccharide-based vaccines are believed to mediate protection is by induction of serotype-specific opsonic antibodies that facilitate bacterial killing by phagocytes (opsonophagocytosis). However, antibodies that are protective against experimental pneumococcal pneumonia in mice but do not promote opsonophagocytic killing in vitro have also been identified 1-3. Such non-opsonic antibodies are associated with bacterial clearance in vivo, but the mechanism by which this occurs is unknown. In this letter, we demonstrate that a protective, non-opsonic serotype 3 pneumococcal capsular polysaccharide-specific monoclonal antibody (MAb) enhances quorum sensing, which results in competence induction and fratricide of serotype 3 pneumococcus. Gene expression profile analysis revealed that the MAb together with the pneumococcal autoinducer, competence stimulating peptide 2 (CSP2), augments differential expression of competence (com) related bacteriocin-like peptide (blp) genes that are known to be involved in pneumococcal fratricide. Taken together, these findings reveal a previously unsuspected mechanism of antibody action, namely, enhancement of quorum sensing and bacterial fratricide. Given that this activity does not require phagocytes, antibodies that function accordingly may hold promise as adjuncts to current vaccines or as desired products of next generation pneumococcal vaccines.
2011-03-01 | GSE27258 | GEO
Project description:Rationale: Respiratory syncytial virus (RSV) and Streptococcus pneumoniae are major respiratory pathogens. Co-infection with RSV and S. pneumoniae is associated with severe and often fatal pneumonia but the molecular basis for this remains unclear. Objectives: To determine if interaction between RSV and pneumococci enhances pneumococcal virulence. Methods: We used confocal microscopy and western blot to identify the receptors involved in direct binding of RSV and pneumococci, the effects of which were studied in both in vivo and in vitro models of infection. Human ciliated respiratory epithelial cell cultures were infected with RSV for 72h and then challenged with pneumococci. Pneumococci were collected after 2h exposure and changes in gene expression determined using qRT-PCR. Results: Following incubation with RSV or purified G protein, pneumococci demonstrated a significant increase in the inflammatory response and bacterial adherence to human ciliated epithelial cultures and markedly increased virulence in a pneumonia model in mice. This was associated with extensive changes in the pneumococcal transcriptome and significant upregulation in the expression of key pneumococcal virulence genes, including the gene for the pneumococcal toxin, pneumolysin. We show that mechanistically this is due to RSV G glycoprotein binding penicillin binding protein 1a. Conclusion: The direct interaction between a respiratory virus protein and the pneumococcus resulting in increased bacterial virulence and worsening disease outcome is a new paradigm in respiratory infection. Comparison of the Streptococcus pneumoniae D39 RSV treated compared to BSA Treated in BEBM medium One condition design comparision of two strains including a dye swap
2014-06-21 | E-GEOD-58425 | biostudies-arrayexpress
Project description:Rationale: Respiratory syncytial virus (RSV) and Streptococcus pneumoniae are major respiratory pathogens. Co-infection with RSV and S. pneumoniae is associated with severe and often fatal pneumonia but the molecular basis for this remains unclear. Objectives: To determine if interaction between RSV and pneumococci enhances pneumococcal virulence. Methods: We used confocal microscopy and western blot to identify the receptors involved in direct binding of RSV and pneumococci, the effects of which were studied in both in vivo and in vitro models of infection. Human ciliated respiratory epithelial cell cultures were infected with RSV for 72h and then challenged with pneumococci. Pneumococci were collected after 2h exposure and changes in gene expression determined using qRT-PCR. Results: Following incubation with RSV or purified G protein, pneumococci demonstrated a significant increase in the inflammatory response and bacterial adherence to human ciliated epithelial cultures and markedly increased virulence in a pneumonia model in mice. This was associated with extensive changes in the pneumococcal transcriptome and significant upregulation in the expression of key pneumococcal virulence genes, including the gene for the pneumococcal toxin, pneumolysin. We show that mechanistically this is due to RSV G glycoprotein binding penicillin binding protein 1a. Conclusion: The direct interaction between a respiratory virus protein and the pneumococcus resulting in increased bacterial virulence and worsening disease outcome is a new paradigm in respiratory infection. Comparison of the Streptococcus pneumoniae D39 Protein P treated compared to Protein GTreated in BEBM medium One condition design comparision of two strains including a dye swap
2014-06-21 | E-GEOD-58424 | biostudies-arrayexpress
Project description:Nonencapsulated Streptococcus pneumoniae (NESp) is an emerging human pathogen that colonizes the nasopharynx and is associated with noninvasive disease such as otitis media (OM), conjunctivitis, and nonbacteremic pneumonia. For decades, expression of a polysaccharide capsule appeared to be necessary for establishment of colonization and development of invasive pneumococcal disease (IPD). Accordingly, the currently licensed pneumococcal vaccines target the polysaccharide capsule. However, NESp expressing the novel oligopeptide importer proteins AliC and AliD have been isolated during IPD. Our study reveals that NESp expressing AliC and AliD have intensified virulence compared to isogenic mutants, and we provide insight about how this pneumococcal population has become associated with IPD. Our data demonstrates that AliC and AliD enhance murine nasopharyngeal colonization and are required for OM in a chinchilla model. Furthermore, AliC and AliD increase pneumococcal survival in chinchilla whole blood and decrease deposition of human C3b on the bacterial surface. As NESp become an increasing threat to public health, our study exposes specific virulence factors to possibly target for a broadened prevention of IPD through vaccination.
2018-01-22 | PXD005178 | Pride