Clostridioides difficile toxins deregulate tight junction proteins.
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE232704 | GEO | 2023/11/29
REPOSITORIES: GEO
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Project description:Toxins TcdA and TcdB are the main virulence factors of Clostridioides difficile, a leading cause of hospital-acquired diarrhea. We investigated the therapeutic potential of inhibiting the biosynthesis of TcdA and TcdB. Accordingly, screening of structurally diverse phytochemicals with medicinal properties identified 18b-glycyrrhetinic acid (enoxolone) as an inhibitor of TcdA and TcdB biosynthesis. Enoxolone also inhibited sporulation. In a CDI colitis model, enoxolone when combined with vancomycin protected mice from becoming moribund and the combination was more effective than vancomycin alone, a standard of care antibiotic for CDI. While enoxolone alone reduced the in vivo load of toxins, the monotherapy did not protect mice from CDI. Affinity based proteomics identified ATP synthase subunit alpha (AtpA) and adenine deaminase (Ade) as possible molecular targets for enoxolone. Silencing of mRNA for Ade and AtpA also reduced toxin biosynthesis, while molecular interaction analysis showed that enoxolone directly bound to Ade. Ade converts adenine to hypoxanthine as an early step in the purine salvage pathway. Metabolomics revealed enoxolone caused cells to accumulate adenosine and deplete hypoxanthine and ATP. Accordingly, supplementation with hypoxanthine partly restored toxin production. Enoxolone also impacted phosphate metabolism by reducing the amounts of cellular phosphate. Thus, supplementation with triethyl phosphate as a source of phosphate also partly restored toxin production. When hypoxanthine and triethyl phosphate were combined, toxin production was fully restored in the presence of enoxolone. Taken together, studies with enoxolone revealed metabolic pathways that affect C. difficile toxin production and could represent potential anti-virulence drug targets.
2022-03-24 | GSE199109 | GEO
Project description:Toxin A and B from Clostridium difficile are the primary virulence factors in Clostridium difficile disease. The changes in gene transcription of human colon epithelial cells were investigated in vitro in order to better understand the many effects of both toxins. HCT-8 cells were treated with 100 ng/ml of either Toxin A or B (TcdA or TcdB). RNA was isolated 2, 6, and 24 hours after addition of toxin from untreated and toxin-treated cells.
2012-01-06 | E-GEOD-29008 | biostudies-arrayexpress
Project description:<p>Clostridioides difficile infection (CDI) is the leading cause of hospital-acquired diarrhea that seriously threaten public health. Disruption of normal gut microbiota by the use of broad-spectrum antimicrobial agents enables C. difficile to proliferate in the colon. The emergence and prevalence of hypervirulent C. difficile strains result in increased morbidity, mortality and recurrence rates of CDI, thus creating a pressing need for novel therapeutics. The multi-domain toxins TcdA and TcdB are the primary determinant of CDI pathogenesis, renders them ideal drug targets in the anti-virulence paradigm. In this study, we identified caffeic acid and its derivatives as active inhibitors of TcdB via a cell-based high-throughput phenotypic screening. Further mechanistic investigations revealed that caffeic acid phenethyl ester (CAPE) could directly bind to TcdB, thus suppressing InsP6-induced autoproteolysis and inhibiting the glucosyltransferase activity. CAPE-treatment remarkably reduces the pathology of CDI in a murine infection model in terms of alleviated diarrhea symptom, decreased bacterial colonization and relieved histopathological lesions. Moreover, CAPE-treatment of C. difficile-challenged mice induces remarkable increase in the diversity and composition of the gut microbiota (e.g. Bacteroides) and alterations of gut metabolites (e.g. adenosine, D-proline and melatonin), which might partially contribute to the therapeutic outcomes of CAPE against CDI. Our results reveal the potential of CAPE as a therapeutic for the management of CDI, or CAPE might be served as a lead compound for the development of anti-virulence drug targeting TcdB.</p>
2024-06-04 | MTBLS9938 | MetaboLights
Project description:Clostridioides difficile (C. difficile) toxins A (TcdA) and B (TcdB) cause antibiotic-associated colitis, increasing morbidity and mortality. Accurate in vitro models are necessary to detect early toxicity kinetics, investigate disease etiology, and develop preclinical models for new therapies. Properties of cancer cell lines and organoids inherently limit these efforts. We developed adult stem cell-derived monolayers of differentiated human colonic epithelium (hCE) with barrier function, investigated the impact of toxin application to apical/basal aspects of monolayers, and evaluated whether a leaky epithelial barrier enhances toxicity. Single-cell RNA-sequencing (scRNAseq) mapped C. difficile-relevant genes to human gut epithelial lineages. Transcriptomics informed timing of stem cell differentiation to achieve in vitro colonocyte maturation like that observed in vivo. Transepithelial electrical resistance (TEER) and fluorescent dextran permeability assays measured cytotoxicity as barrier loss post-toxin exposure. Leaky epithelial barriers were induced with diclofenac. scRNAseq demonstrated broad and variable toxin receptor expression across human gut lineages. Absorptive colonocytes displayed generally enhanced toxin receptor, Rho GTPase, and cell junction expression. 22-day differentiated Caco-2 cells remained immature whereas hCE monolayers were similar to mature colonocytes. hCE monolayers exhibited high barrier function after 1-day differentiation. Basal TcdA/B application to monolayers caused greater toxicity and apoptosis. Diclofenac induced leaky hCE monolayers and enhanced toxicity of apical TcdB exposure. Apical/basal toxicities are uncoupled with more rapid onset and increased magnitude of basal toxicity. Leaky paracellular junctions enhance toxicity of apical TcdB exposure. hCE monolayers represent a physiologically relevant and sensitive culture system to evaluate the impact of microbial toxins on gut epithelium.
2023-02-13 | GSE223605 | GEO
Project description:Toxin A (TcdA) and Toxin B (TcdB), of the pathogen Clostridium difficile, are virulence factors that cause gross pathologic changes (e.g. inflammation, secretion, and diarrhea) in the infected host, yet the molecular and cellular pathways leading to observed host responses are poorly understood. To address this gap, TcdA and/or TcdB were injected into the ceca of mice and the genome-wide transcriptional response of epithelial layer cells was examined. Bioinformatic analysis of gene expression identified sets of cooperatively expressed genes. Further analysis of inflammation associated genes revealed dynamic chemokine responses. In total, 32 samples were analyzed (one microarray per mouse). The sample groups are separated by two factors: Toxin (TcdA, TcdB, TcdA+TcdB, or Sham injection) and endpoint (2, 6, or 16h). TcdA+B at 16h was not included, leaving 11 sample groups. Each sample group included biological triplicates, except TcdA+TcdB at 6h (one array) and Sham injection at 16h (four arrays).
2013-07-30 | E-GEOD-44091 | biostudies-arrayexpress
Project description:Clostridioides difficile toxins deregulate tight junction proteins.
| PRJNA973611 | ENA
Project description:Clostridium difficile is an important nosocomial pathogen and the leading cause of hospital-acquired diarrhea. Antibiotic use is the primary risk factor for the development of C. difficile-associated disease because it disrupts normal protective gut flora and enables C. difficile to colonize the colon. C. difficile damages host tissue by secreting toxins and disseminates by forming spores. The toxin-encoding genes, tcdA and tcdB are part of a pathogenicity locus, which also encodes the gene tcdR that codes for the toxin genes positive regulator. TcdR is an alternate sigma factor that initiates transcription of tcdA and tcdB at their promoters. Alternative sigma factors are known to regulate virulence and virulence associated genes in many pathogenic bacteria. We created a tcdR mutant in the epidemic-type C. difficile R20291 strain in an attempt to identify the global role of tcdR. A site-directed mutation in tcdR affected both toxin production and sporulation in C. difficile R20291. Spores derived from the tcdR mutant were found to be mildly temperature sensitive. Moreover, nearly two fold more taurocholate was needed to germinate spores from the tcdR mutant than the spores prepared from the wild-type parent strain. Comparison of the tcdR mutant transcriptome with the parent strain revealed many differentially expressed late sporulation genes in the tcdR mutant. These data suggests that gene regulatory networks of toxin production and sporulation in Clostridium difficile are linked with each other.
2017-03-07 | GSE85395 | GEO
Project description:Clostridium difficile (Cd) is a gram-positive, spore-forming bacterium and the primary cause of nosocomial diarrhea and pseudomembranous colitis. The pathogenicity of Cd has been linked to its production of TcdA and TcdB. While they cause fluid secretion, inflammation, and colonic damage, their respective and synergistic roles have been difficult to ascertain. In infection animal model, TcdB has been demonstrated to be a key virulence factor, and TcdB causes obvious damage in human and porcine colonic explants. Using the colonic epithelia derived from cloned colonic stem cells, we have developed a model to test the response to TcdB. Epithelia generated in air-liquid interface cultures from cloned transverse colon stem cells were challenged with TcdB at different concentrations and durations.
2015-05-29 | GSE63880 | GEO
Project description:Toxin A (TcdA) and Toxin B (TcdB), of the pathogen Clostridium difficile, are virulence factors that cause gross pathologic changes (e.g. inflammation, secretion, and diarrhea) in the infected host, yet the molecular and cellular pathways leading to observed host responses are poorly understood. To address this gap, TcdA and/or TcdB were injected into the ceca of mice and the genome-wide transcriptional response of epithelial layer cells was examined. Bioinformatic analysis of gene expression identified sets of cooperatively expressed genes. Further analysis of inflammation associated genes revealed dynamic chemokine responses.
2013-07-30 | GSE44091 | GEO
Project description:A Clostridioides difficile infection (CDI) is the most common nosocomial infection worldwide. The main virulence factors are TcdA and TcdB, which inhibit small Rho-GTPases. Inhibition of small Rho-GTPases leads to the so-called cytopathic effect, a reorganization of the actin cytoskeleton, an impairment of the colon epithelium barrier function, and inflammation. Additionally, TcdB induces a necrotic cell death termed pyknosis in vitro independently from its glucosyltransferas-es characterized by chromatin condensation and ROS production. To understand the underlying mechanism of this pyknotic effect, we conducted a large-scale phosphoproteomic study. We in-cluded the analysis of alterations in the phosphoproteome after treatment with TcdA, that was investigated for the first time. TcdA exhibit no glucosyltransferase-independent effect and was, thus, a good control to elucidate the underlying mechanism of the glucosyltransferase inde-pendent effect of TcdB. We found RAS to be a central upstream regulator for the glucosyltrans-ferase independent effect of TcdB. Inhibition of RAS leads to a 68% reduction in necrosis. Further analysis revealed apolipoprotein C-III (APOC3) as a possible crucial factor of CDI induced in-flammation in vivo.
2022-05-19 | PXD031726 | Pride