Deletion of FaeG alleviated Enterotoxigenic Escherichia coli F4ac-induced apoptosis in the intestine.
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ABSTRACT:
SUBMITTER: Xia P
PROVIDER: S-EPMC7973317 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Enterotoxigenic Escherichia coli (ETEC) F4ac is a major determinant of diarrhea and mortality in neonatal and young pigs. Susceptibility to ETEC F4ac is governed by the intestinal receptor specific for the bacterium and is inherited as a monogenic dominant trait. To identify the receptor gene (F4acR), we first mapped the locus to a 7.8-cM region on pig chromosome 13 using a genome scan with 194 microsatellite markers. A further scan with high density markers on chromosome 13 refined the locus to a 5.7-cM interval. Recombination breakpoint analysis defined the locus within a 2.3-Mb region. Further genome-wide mapping using 39,720 informative SNPs revealed that the most significant markers were proximal to the MUC13 gene in the 2.3-Mb region. Association studies in a collection of diverse outbred populations strongly supported that MUC13 is the most likely responsible gene. We characterized the porcine MUC13 gene that encodes two transcripts: MUC13A and MUC13B. Both transcripts have the characteristic PTS regions of mucins that are enriched in distinct tandem repeats. MUC13B is predicated to be heavily O-glycosylated, forming the binding site of the bacterium; while MUC13A does not have the O-glycosylation binding site. Concordantly, 127 independent pigs homozygous for MUC13A across diverse breeds are all resistant to ETEC F4ac, and all 718 susceptible animals from the broad breed panel carry at least one MUC13B allele. Altogether, we conclude that susceptibility towards ETEC F4ac is governed by the MUC13 gene in pigs. The finding has an immediate translation into breeding practice, as it allows us to establish an efficient and accurate diagnostic test for selecting against susceptible animals. Moreover, the finding improves our understanding of mucins that play crucial roles in defense against enteric pathogens. It revealed, for the first time, the direct interaction between MUC13 and enteric bacteria, which is poorly understood in mammals.
| S-EPMC3440394 | biostudies-literature
Project description:Enterotoxigenic Escherichia coli (ETEC) is capable of invading epithelial cell lines derived from the human ileum and colon. Two separate invasion loci (tia and tib) that direct noninvasive E. coli strains to adhere to and invade cultured human intestine epithelial cells have previously been isolated from the classical ETEC strain H10407. The tib locus directs the synthesis of TibA, a 104-kDa outer membrane glycoprotein. Synthesis of TibA is directly correlated with the adherence and invasion phenotypes of the tib locus, suggesting that this protein is an adhesin and invasin. Here we report the purification of TibA and characterization of its biological activity. TibA was purified by continuous-elution preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purified TibA was biotin labeled and then shown to bind to HCT8 human ileocecal epithelial cells in a specific and saturable manner. Unlabeled TibA competed with biotin-labeled TibA, suggesting the presence of a specific TibA receptor in HCT8 cells. These results show that TibA acts as an adhesin. Polyclonal anti-TibA antiserum inhibited invasion of ETEC strain H10407 and of recombinant E. coli bearing tib locus clones, suggesting that TibA also acts as an invasin. The ability of TibA to direct epithelial cell adhesion suggests a role for this protein in ETEC pathogenesis.
| S-EPMC97854 | biostudies-literature
Project description:Enterotoxigenic Escherichia coli (ETEC) that expresses F4ac fimbriae is the major pathogenic microorganism responsible for bacterial diarrhea in neonatal piglets. The susceptibility of piglets to ETEC F4ac is determined by a specific receptor on the small intestinal epithelium surface. We performed an iTRAQ-labeled quantitative proteome analysis using a case-control design in which susceptible and resistant full-sib piglets were compared for the protein expression levels. Two thousand two hundred forty-nine proteins were identified, of which 245 were differentially expressed (fold change > 1.5, FDR-adjusted P < 0.05). The differentially expressed proteins fell into four functional classes: (I) cellular adhesion and binding, (II) metabolic process, (III) apoptosis and proliferation, and (IV) immune response. The integrin signaling pathway merited particular interest based on a pathway analysis using statistical overexpression and enrichment tests. Genomic locations of the integrin family genes were determined based on the most recent porcine genome sequence assembly (Sscrofa11.1). Only one gene, ITGB5, which encodes the integrin ?5 subunit that assorts with the ?v subunit to generate integrin ?v?5, was located within the SSC13q41 region between 13:133161078 and 13:139609422, where strong associations of markers with the ETEC F4ac susceptibility were found in our previous GWAS results. To identify whether integrin ?v?5 is the ETEC F4acR, we established an experimental model for bacterial adhesion using IPEC-J2 cells. Then, the ITGB5 gene was knocked out in IPEC-J2 cell lines using CRISPR/Cas9, resulting in a biallelic deletion cell line (ITGB5 -/-). Disruption of ITGB5 significantly reduced ETEC F4ac adhesion to porcine intestinal epithelial cells. In contrast, overexpression of ITGB5 significantly enhanced the adhesion. A GST pull-down assay with purified FaeG and ITGB5 also showed that FaeG binds directly to ITGB5. Together, the results suggested that ITGB5 is a key factor affecting the susceptibility of piglets to ETEC F4ac.
| S-EPMC6927286 | biostudies-literature
Project description:The development of an early complex gut microbiota may play an important role in the protection against intestinal dysbiosis later in life. The significance of the developed microbiota for gut barrier functionality upon interaction with pathogenic or beneficial bacteria is largely unknown. The transcriptome of differently perfused jejunal loops of 12 caesarian-derived pigs, neonatally associated with microbiota of different complexity, was studied. Piglets received pasteurized sow colostrum at birth (d0), a starter microbiota (Lactobacillus amylovorus (LAM), Clostridium glycolicum, and Parabacteroides) on d1-d3, and a placebo inoculant (simple association, SA) or an inoculant consisting of sow's diluted feces (complex association, CA) on d3-d4. On d 26-37, jejunal loops were perfused for 8 h with either enterotoxigenic Escherichia coli F4 (ETEC), purified F4 fimbriae, LAM or saline control (CTRL). Gene expression of each intestinal loop was analyzed by Affymetrix Porcine Gene 1.1_ST array strips. Gene Set Enrichment Analysis was performed on expression values. Compared to CTRL, 184 and 74; 2 and 139; 2 and 48 gene sets, were up- and down-regulated by ETEC, F4 and LAM, respectively. ETEC up-regulated networks related to inflammatory and immune responses, RNA processing, and mitosis. There was a limited overlap in up-regulated gene sets between ETEC and F4 fimbriae. LAM down-regulated genes related to inflammatory and immune responses, as well as to cellular compound metabolism. In CA pigs, 57 gene sets were up-regulated by CA, while 73 were down-regulated compared to SA. CA up-regulated gene sets related to lymphocyte modulation and to cellular defense in all loop perfusions. In CA pigs, compared to SA pigs, genes for chemokine and cytokine activity and for response to external stimuli were down-regulated in ETEC-perfused loops and up-regulated in CTRL. The results highlight the importance of the nature of neonatal microbial colonization in the response to microbial stimuli later in life.
| S-EPMC6116929 | biostudies-literature
Project description:BackgroundEnterotoxigenic Escherichia coli (ETEC) causes diarrhea in humans, cows, and pigs. The gut microbiota underlies pathology of several infectious diseases yet the role of the gut microbiota in the pathogenesis of ETEC-induced diarrhea is unknown.ResultsBy using an ETEC induced diarrheal model in piglet, we profiled the jejunal and fecal microbiota using metagenomics and 16S rRNA sequencing. A jejunal microbiota transplantation experiment was conducted to determine the role of the gut microbiota in ETEC-induced diarrhea. ETEC-induced diarrhea influenced the structure and function of gut microbiota. Diarrheal piglets had lower Bacteroidetes: Firmicutes ratio and microbiota diversity in the jejunum and feces, and lower percentage of Prevotella in the feces, but higher Lactococcus in the jejunum and higher Escherichia-Shigella in the feces. The transplantation of the jejunal microbiota from diarrheal piglets to uninfected piglets leaded to diarrhea after transplantation. Microbiota transplantation experiments also supported the notion that dysbiosis of gut microbiota is involved in the immune responses in ETEC-induced diarrhea.ConclusionWe conclude that ETEC infection influences the gut microbiota and the dysbiosis of gut microbiota after ETEC infection mediates the immune responses in ETEC infection.
| S-EPMC6282381 | biostudies-literature
Project description:BackgroundDiarrhea represents one of the most frequent major problems during piglets' neonatal and post-weaning periods leading to tremendous economic losses in the swine industry. Enterotoxigenic Escherichia coli (ETEC) F4 is regarded as the most important cause of diarrhea in piglets. However, some pigs are naturally resistant to those diarrheas caused by ETEC-F4, because they have no F4 receptors (F4R) on their small intestine epithelial cells that allow F4 fimbriae attachment. Thus, our study characterized a complete transcriptome of small intestine epithelial cells of Large White piglets using RNA-Seq. The aim of the study was to identify DEGs with regard to differences in the F4R phenotypes and SNP (C/T) genotypes at ITGB5 and important pathways associated with ETEC-F4ac susceptibility in small intestine epithelial cells of Large White piglets and derive molecular markers as a result of loss of F4acR in swine.MethodsA total of eight samples of small intestine epithelial cells obtained from Large White piglets (35 days old) used in this study were selected on the basis of two criteria. One was the adhesion phenotype to ETEC-F4ac fimbriae, and the other was the comparison of ITGB5 SNP (C > T) genotype sequences across all the samples. The samples were then divided into two groups, non-adhesive with CC genotype (n = 4), and adhesive with TT genotype (n = 4).ResultsMore down-regulated DEGs (p < 0.05, |log2FC| > 2) were detected in the comparison of non-adhesive vs. adhesive small intestine epithelial cells in the present study. Six genes, of which two (CNGA4, SLC25A31) exclusively expressed and four (HCN4, MYLK, KCNMA1, and KCNMB1) DEGs with up-regulation pattern in adhesive (F4R positive) pigs were involved in two pathways associated with diarrhea. The DEGs with up-regulation pattern in non-adhesive (F4R negative) pigs were mostly engaged in multiple immune response-related pathways.ConclusionThe results provide insights on the biology of the phenotypes of F4R positive and negative pigs. One gene (MYLK) located on SSC13 locus for F4acR strongly support that it might have played a role in the adhesion phenotype which was obviously detected by adhesion assay in adhesive (F4R positive) group.
| S-EPMC7056726 | biostudies-literature
Project description:Escherichia coli, one of the most abundant bacterial species in the human gut microbiota, has developed a mutualistic relationship with its host, regulating immunological responses. In contrast, enterotoxigenic E. coli (ETEC), one of the main etiologic agents of diarrheal morbidity and mortality in children under the age of five in developing countries, has developed mechanisms to reduce the immune-activator effect to carry out a successful infection. Following infection, the host cell initiates the shutting-off of protein synthesis and stress granule (SG) assembly. This is mostly mediated by the phosphorylation of translation initiator factor 2α (eIF2α). We therefore evaluated the ability of a non-pathogenic E. coli strain (E. coli HS) and an ETEC strain (ETEC 1766a) to induce stress granule assembly, even in response to exogenous stresses. In this work, we found that infection with E. coli HS or ETEC 1766a prevents SG assembly in Caco-2 cells treated with sodium arsenite (Ars) after infection. We also show that this effect occurs through an eIF2α phosphorylation (eIF2α-P)-dependent mechanism. Understanding how bacteria counters host stress responses will lay the groundwork for new therapeutic strategies to bolster host cell immune defenses against these pathogens.
| S-EPMC7822485 | biostudies-literature
Project description:The intestinal peptide hormones guanylin (GN) and uroguanylin (UGN) interact with the epithelial cell receptor guanylate cyclase C to regulate fluid homeostasis. Some enterotoxigenic Escherichia coli (ETEC) produce heat-stable enterotoxin (ST), which induces diarrhea by mimicking GN and UGN. Plasma concentrations of prohormones of GN (proGN) and UGN (proUGN) are reportedly decreased during chronic diarrheal diseases. Here we investigate whether prohormone concentrations also drop during acute diarrhea caused by ST-producing ETEC strains TW10722 and TW11681. Twenty-one volunteers were experimentally infected with ETEC. Blood (n = 21) and urine (n = 9) specimens were obtained immediately before and 1, 2, 3, and 7 days after ETEC ingestion. Concentrations of proGN and proUGN were measured by ELISA. Urine electrolyte concentrations were measured by photometry and mass spectrometry. Ten volunteers developed diarrhea (D group), and eleven did not (ND group). In the D group, plasma proGN, but not proUGN, concentrations were substantially reduced on days 2 and 3, coinciding with one day after diarrhea onset. No changes were seen in the ND group. ETEC diarrhea also seemed to affect diuresis, the zinc/creatinine ratio, and sodium and chloride secretion levels in urine. ETEC-induced diarrhea causes a reduction in plasma proGN and could potentially be a useful marker for intestinal isotonic fluid loss.
| S-EPMC10458898 | biostudies-literature
Project description:Enterotoxigenic Escherichia coli (ETEC) is a common cause of diarrhea among children living in and among travelers visiting developing countries. Human ETEC strains represent an epidemiologically and phenotypically diverse group of pathogens, and there is a need to identify natural groupings of these organisms that may help to explain this diversity. Here, we sought to identify most of the important human ETEC lineages that exist in the E. coli population, because strains that originate from the same lineage may also have inherited many of the same epidemiological and phenotypic traits. We performed multilocus sequence typing (MLST) on 1,019 ETEC isolates obtained from humans in different countries and analyzed the data against a backdrop of MLST data from 1,250 non-ETEC E. coli and eight ETEC isolates from pigs. A total of 42 different lineages were identified, 15 of which, representing 792 (78%) of the strains, were estimated to have emerged >900 years ago. Twenty of the lineages were represented in more than one country. There was evidence of extensive exchange of enterotoxin and colonization factor genes between different lineages. Human and porcine ETEC have probably emerged from the same ancestral ETEC lineage on at least three occasions. Our findings suggest that most ETEC strains circulating in the human population today originate from well-established, globally widespread ETEC lineages. Some of the more important lineages identified here may represent a smaller and more manageable target for the ongoing efforts to develop effective ETEC vaccines.
| S-EPMC2916599 | biostudies-literature
Project description:Enterotoxigenic Escherichia coli (ETEC) infections are a significant cause of diarrheal disease and infant mortality in developing countries. Studies of ETEC pathogenesis relevant to vaccine development have been greatly hampered by the lack of a suitable small-animal model of infection with human ETEC strains. Here, we demonstrate that adult immunocompetent outbred mice can be effectively colonized with the prototypical human ETEC H10407 strain (colonization factor antigen I; heat-labile and heat-stable enterotoxin positive) and that production of heat-labile holotoxin provides a significant advantage in colonization of the small intestine in this model.
| S-EPMC1360293 | biostudies-literature