Homo sapiens
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PROVIDER: PRJNA289148 | ENA |
REPOSITORIES: ENA
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Project description:The Gram-negative bacterium Campylobacter jejuni is a major cause of foodborne disease in humans. After infection, C. jejuni rapidly colonizes the mucus layer of the small and large intestine and induces a potent pro-inflammatory response characterized by the production of a large repertoire of cytokines, chemokines, and innate effector molecules, resulting in (bloody) diarrhea. The virulence mechanisms by which C. jejuni causes this intestinal response are still largely unknown. Here we show that C. jejuni releases a potent pro-inflammatory compound into its environment, which activates an NF-B-mediated pro-inflammatory response including the induction of CXCL8, CXCL2, TNFAIP2 and PTGS2. This response was dependent on a functional ALPK1 receptor and independent of Toll-like Receptor and Nod-like Receptor signaling. Chemical characterization, inactivation of the heptose-biosynthesis pathway by the deletion of the hldE gene and in vitro engineering identified the released factor as the LOS-intermediate ADP-heptose and/or related heptose phosphates. During C. jejuni infection of intestinal cells, the ALPK1-NF-kB axis was potently activated by released heptose metabolites without the need for a type III or type IV injection machinery. Our results classify ADP-heptose and/or related heptose phosphates as a major virulence factor of C. jejuni that may play an important role during Campylobacter infection in humans.
2021-07-15 | GSE70610 | GEO
Project description:The symptoms of infectious diarrheal disease are mediated by the interplay between the host and pathogen. Campylobacter jejuni is the leading bacterial cause of diarrhea worldwide due to its near-ubiquitous zoonotic association with poultry. One of the outstanding questions is what factors drive the intestinal inflammation during the development of C. jejuni-mediated disease. Specifically, it is not known the extent to which the bacteria are responsible for the diarrheal symptoms via cell necrosis, or whether there is immune cell recruitment prior to tissue damage. To determine the stepwise process of inflammation that leads to diarrhea, we used a piglet ligated intestinal loop model to study the intestinal environment in response to C. jejuni. Pigs were chosen due to the anatomical similarity of the porcine intestine to the human intestine, as the basis of disease modeling is to understand the process of human disease. Using immunoassays and proteomic approaches, we found that neutrophils are most likely the predominant cell type recruited to the intestines of C. jejuni infected animals. In the lumen of the intestine, a number of neutrophil related proteins increased during C. jejuni infection, including proteins related to neutrophil migration (elastase and MMP9), actin reorganization and bacterial uptake (Cdc42, WAVE-2, and Arp2/3), and antimicrobial proteins (lipocalin-2, myeloperoxidase, S100A8, and S100A9). The appearance of neutrophils also corresponds with increases of both IL-8 and TNF-a. Compared to infection with the C. jejuni wild-type strain, infection with the noninvasive C. jejuni ∆ciaD mutant resulted in a blunted inflammatory response, with less inflammatory cytokines and neutrophil markers. These findings indicate that intestinal inflammation is driven by C. jejuni virulence, and that resident intestinal cells precipitate the inflammatory response. Using this new disease model, we have developed a platform to study the early immune events during C. jejuni infection.
2020-10-07 | GSE147629 | GEO
Project description:Campylobacter jejuni infection often results in bloody, inflammatory diarrhea, indicating bacterial disruption and invasion of the intestinal epithelium. Whilst C. jejuni infection can be reproduced in vitro using intestinal epithelial cell (IEC) lines, low numbers of bacteria invading IECs do not reflect these clinical symptoms. Performing in vitro assays under atmospheric oxygen conditions is neither optimal for microaerophilic C. jejuni nor reflects the low oxygen environment of the intestinal lumen. A Vertical Diffusion Chamber (VDC) model system creates microaerobic conditions at the apical surface and aerobic conditions at the baso-lateral surface of cultured IECs producing an in vitro system that closely mimics in vivo conditions in the human intestine. Nine-fold increases in interacting and eighty-fold increases in intracellular C. jejuni 11168H wild-type strain bacteria were observed after 24 hours co-culture with Caco-2 IECs in VDCs with microaerobic conditions at the apical surface compared to aerobic conditions. Increased bacterial interaction was matched by an enhanced and directional host innate immune response, particularly an increased baso-lateral secretion of the pro-inflammatory chemokine IL-8. Analysis of the invasive ability of a non-motile C. jejuni 11168H rpoN mutant in the VDC model system indicates that motility is an important factor in the early stages of bacterial invasion. The first report of the use of a VDC model system for studying the interactions of an invasive bacterial pathogen with IECs demonstrates the importance of performing such experiments under conditions that represent the in vivo situation and will allow novel insights into C. jejuni pathogenic mechanisms. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-125]
2012-04-02 | E-BUGS-125 | biostudies-arrayexpress
Project description:Campylobacter jejuni is a highly prevalent food-borne pathogen that causes diarrhoeal disease in humans. A natural zoonotic, it must overcome significant stresses both in vivo and during transmission despite the absence of several traditional stress response genes. Its ability to interact with and invade human intestinal epithelial cells closely correlates with virulence. A C. jejuni microarray-based screen revealed that several known virulence genes and several uncharacterized genes, including spoT, were rapidly upregulated during infection of human epithelial cells. spoT and its homologue relA have been shown in other bacteria to regulate the stringent response, an important stress response that to date had not been demonstrated for C. jejuni. We have found that C. jejuni mounts a stringent response that is regulated by spoT. Detailed analyses of a C. jejuni delta spoT mutant revealed that the stringent response is required for several specific stress, transmission and antibiotic resistance-related phenotypes. These include stationary phase survival, growth and survival under low CO2/high O2 conditions, and rifampicin resistance. A secondary suppressor strain that specifically rescues the low CO2 growth defect of the delta spoT mutant was also isolated. The stringent response additionally proved to be required for the virulence-related phenotypes of adherence, invasion, and intracellular survival in two human epithelial cell culture models of infection; spoT is the first C. jejuni gene shown to participate in longer term survival in epithelial cells. Comparing wt to the delta spoT mutant also revealed a strong correlation between gene expression profiles and phenotype differences observed. Together, these data demonstrate a critical role for the C. jejuni stringent response in multiple aspects of C. jejuni biology and pathogenesis.
2005-08-23 | E-SMDB-3292 | biostudies-arrayexpress
Project description:Consumption of contaminated poultry products is one of the main sources of human campylobacteriosis, of which Campylobacter jejuni subsp. jejuni (C. jejuni) and C. coli are responsible for approximately 98% of the cases. The ceca of commercial turkeys are the main anatomical site where Campylobacter asymptomatically colonizes. We have previously colonized the ceca of commercial turkey poults with C. jejuni, and demonstrated acute changes in cytokine gene expression in cecal tissue and histologically scored intestinal lesions at 2 days post-inoculation (dpi). The host-response of turkeys to C. coli colonization is unknown. Cecal tonsils (CT) are an important part of the gastrointestinal-associated lymphoid tissue that function to sample material passing in and out of the ceca and generating immune responses against intestinal pathogens. The CT immune response towards Campylobacter is unknown. In this study, we generated a C. coli kanamycin-resistant construct (CcK) for enumeration from cecal contents after experimental challenge. In vitro analysis of CcK demonstrated no changes in motility when compared to the parent isolate, but in vitro growth rates were significantly different than the parent strain. Poults were inoculated by oral gavage with CcK (5x10^7 cfu) or sterile-media (mock-colonized), and euthanized at 1 and 3 dpi. At both time points, CcK was recovered from cecal contents, but not from the mock-colonized group. As a marker of acute inflammation, serum alpha-1 acid glycoprotein was significantly elevated at 3 dpi in CcK inoculated poults compared to mock-infected samples. Significant histological lesions were detected in cecal and CT tissues of CcK colonized poults at 1 and 3 dpi, respectively. RNAseq analysis identified 250 differentially expressed genes (DEG) in CT from CcK colonized poults at 3 dpi, of which 194 were upregulated and 56 were downregulated. From the DEG, 9 significantly enriched biological pathways were identified, including platelet aggregation, response to oxidative stress and negative regulation of oxidative stress-induced intrinsic apoptotic signaling pathway. These data suggest that C. coli induced an acute inflammatory response in the intestinal tract of poults, and that platelet aggregation and oxidative stress in the CT may affect the turkey’s ability to resist Campylobacter colonization. Results from this study provide insight into host-response of the turkey CT to Campylobacter colonization. These findings will help to develop and test Campylobacter mitigation strategies to promote food safety in commercial turkeys.
2020-10-01 | GSE158639 | GEO
Project description:Campylobacter jejuni is a highly prevalent food-borne pathogen that causes diarrhoeal disease in humans. A natural zoonotic, it must overcome significant stresses both in vivo and during transmission despite the absence of several traditional stress response genes. Its ability to interact with and invade human intestinal epithelial cells closely correlates with virulence. A C. jejuni microarray-based screen revealed that several known virulence genes and several uncharacterized genes, including spoT, were rapidly upregulated during infection of human epithelial cells. spoT and its homologue relA have been shown in other bacteria to regulate the stringent response, an important stress response that to date had not been demonstrated for C. jejuni. We have found that C. jejuni mounts a stringent response that is regulated by spoT. Detailed analyses of a C. jejuni delta spoT mutant revealed that the stringent response is required for several specific stress, transmission and antibiotic resistance-related phenotypes. These include stationary phase survival, growth and survival under low CO2/high O2 conditions, and rifampicin resistance. A secondary suppressor strain that specifically rescues the low CO2 growth defect of the delta spoT mutant was also isolated. The stringent response additionally proved to be required for the virulence-related phenotypes of adherence, invasion, and intracellular survival in two human epithelial cell culture models of infection; spoT is the first C. jejuni gene shown to participate in longer term survival in epithelial cells. Comparing wt to the delta spoT mutant also revealed a strong correlation between gene expression profiles and phenotype differences observed. Together, these data demonstrate a critical role for the C. jejuni stringent response in multiple aspects of C. jejuni biology and pathogenesis. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
2005-08-27 | E-GEOD-3209 | biostudies-arrayexpress
Project description:Campylobacter jejuni is a highly prevalent food-borne pathogen that causes diarrhoeal disease in humans. A natural zoonotic, it must overcome significant stresses both in vivo and during transmission despite the absence of several traditional stress response genes. Its ability to interact with and invade human intestinal epithelial cells closely correlates with virulence. A C. jejuni microarray-based screen revealed that several known virulence genes and several uncharacterized genes, including spoT, were rapidly upregulated during infection of human epithelial cells. spoT and its homologue relA have been shown in other bacteria to regulate the stringent response, an important stress response that to date had not been demonstrated for C. jejuni. We have found that C. jejuni mounts a stringent response that is regulated by spoT. Detailed analyses of a C. jejuni delta spoT mutant revealed that the stringent response is required for several specific stress, transmission and antibiotic resistance-related phenotypes. These include stationary phase survival, growth and survival under low CO2/high O2 conditions, and rifampicin resistance. A secondary suppressor strain that specifically rescues the low CO2 growth defect of the delta spoT mutant was also isolated. The stringent response additionally proved to be required for the virulence-related phenotypes of adherence, invasion, and intracellular survival in two human epithelial cell culture models of infection; spoT is the first C. jejuni gene shown to participate in longer term survival in epithelial cells. Comparing wt to the delta spoT mutant also revealed a strong correlation between gene expression profiles and phenotype differences observed. Together, these data demonstrate a critical role for the C. jejuni stringent response in multiple aspects of C. jejuni biology and pathogenesis. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
2005-08-27 | GSE3209 | GEO
Project description:Major foodborne bacterial pathogens, such as Campylobacter jejuni, have devised complex strategies to establish and foster intestinal infections. For more than two decades researchers have used immortalized cell lines derived from human intestinal tissue to dissect C. jejuni-host cell interactions. Known from these studies is that C. jejuni virulence is multifactorial, requiring a coordinated response to produce virulence factors that facilitate the bacterium’s host-cell interactions. This study was initiated to identify C. jejuni proteins that contribute to adaptation to the host cell environment and cellular invasion. We demonstrated that C. jejuni responds to INT 407 and Caco-2 cells in a similar fashion at the cellular and molecular levels. Active protein synthesis was found to be required for C. jejuni to maximally invade these host cells. Proteomic and transcriptomic approaches were then used to define the protein and gene expression profiles of C. jejuni co-cultured with cells. By focusing on those genes showing increased expression by C. jejuni when co-cultured with epithelial cells, we discovered that C. jejuni quickly adapts to co-culture with epithelial cells by synthesizing gene products that enable it to acquire specific amino acids for growth, scavenge for inorganic molecules including iron, resist reactive oxygen/nitrogen species, and promote bacteria-host cell interactions. Based on these findings, we selected a subset of the genes involved in chemotaxis and the regulation of flagellar assembly and generated C. jejuni deletion mutants for phenotypic analysis. Binding and internalization assays revealed significant differences in the interaction of C. jejuni chemotaxis and flagellar regulatory mutants. The identification of genes involved in C. jejuni adaptation to culture with host cells provides new insights into the infection process.
2019-04-11 | GSE114909 | GEO
Project description:Campylobacter jejuni is the leading bacterial cause of human gastroenteritis worldwide. Despite stringent microaerobic growth requirements, C. jejuni is ubiquitous in the aerobic environment. C. jejuni must possess finely tuned regulatory systems to sense and adapt to external stimuli such as oxidative and aerobic (O2) stress. Re-annotation of the C. jejuni NCTC11168 genome sequence identified Cj1556 (originally annotated as a hypothetical protein) as a MarR family transcriptional regulator and further bioinformatic analysis indicated a role in regulating the oxidative stress response. A C. jejuni 11168H Cj1556 mutant exhibited increased sensitivity to oxidative and aerobic stress, decreased ability for intracellular survival in both Caco-2 human intestinal epithelial cells and J774A.1 mouse macrophages and a reduction in virulence in the Galleria mellonella infection model. Microarray analysis of gene expression changes in the Cj1556 mutant compared to the wild-type strain indicated negative autoregulation of Cj1556 expression and down-regulation of genes associated with oxidative and aerobic stress responses, such as katA, perR and hspR. cprS, which encodes a sensor kinase involved in the regulation of biofilm formation, was also up-regulated in the Cj1556 mutant and subsequent studies showed that the Cj1556 mutant had a reduced ability to form biofilms. Protein interaction studies confirmed the binding of recombinant Cj1556 to a region upstream of Cj1556. This study has identified a novel C. jejuni transcriptional regulator Cj1556 that is involved in oxidative and aerobic stress responses and is important for the survival of C. jejuni in the natural environment and in vivo. This newly identified regulator was designated CosR (Campylobacter oxidative stress Regulator). Data is also available from <ahref=""http://bugs.sgul.ac.uk/E-BUGS-119"" target=""_blank"">BuG@Sbase</a>
2012-01-23 | E-BUGS-119 | biostudies-arrayexpress
Project description:DksA is well-known for its regulatory role in the transcription of ribosomal RNA and genes involved in amino acid synthesis in many bacteria. DksA is also reported to control expression of virulence genes in pathogenic bacteria. Here, we elucidated the roles of the DksA-like protein (CJJ81176_0160, Cj0125c) in the pathogenesis of Campylobacter jejuni. Like in other bacteria, transcription of stable RNA was repressed by DksA under stressful conditions in C. jejuni. Transcriptomic and proteomic analyses of C. jejuni 81-176 and its isogenic dksA mutant showed differential expression of many genes involved in iron-related metabolism, flagellar synthesis and amino acid metabolism. Also the dksA mutant of C. jejuni demonstrated a decreased ability to invade into intestinal cells and to induce release of interleukin-8 from intestinal cells. These results suggest the DksA-like protein plays an important regulatory role in the physiology and virulence of C. jejuni. Keywords: dksA mutation of Campylobacter jejuni
2008-05-06 | GSE9866 | GEO