scholarly journals Analysis of the σERegulon in Crohn's Disease-Associated Escherichia coli Revealed Involvement of thewaaWVLOperon in Biofilm Formation

2015 ◽  
Vol 197 (8) ◽  
pp. 1451-1465 ◽  
Author(s):  
Benoit Chassaing ◽  
Estelle Garénaux ◽  
Jessica Carriere ◽  
Nathalie Rolhion ◽  
Yann Guérardel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Intestinal Mucosa ◽  
Biofilm Formation ◽  
Intestinal Epithelial ◽  
Content Type ◽  
E Coli ◽  
Gut Mucosa ◽  
Pathway Inhibition

ABSTRACTIleal lesions of patients with Crohn's disease are colonized by adherent-invasiveEscherichia coli(AIEC), which is able to adhere to and to invade intestinal epithelial cells (IEC), to replicate within macrophages, and to form biofilms on the surface of the intestinal mucosa. Previous analyses indicated the involvement of the σEpathway in AIEC-IEC interaction, as well as in biofilm formation, with σEpathway inhibition leading to an impaired ability of AIEC to colonize the intestinal mucosa and to form biofilms. The aim of this study was to characterize the σEregulon of AIEC strain LF82 in order to identify members involved in AIEC phenotypes. Using comparativein silicoanalysis of the σEregulon, we identified thewaaWVLoperon as a new member of the σEregulon in reference AIEC strain LF82. We determined that thewaaWVLoperon is involved in AIEC lipopolysaccharide structure and composition, and thewaaWVLoperon was found to be essential for AIEC strains to produce biofilm and to colonize the intestinal mucosa.IMPORTANCEAn increased prevalence of adherent-invasiveEscherichia coli(AIEC) bacteria was previously observed in the intestinal mucosa of Crohn's disease (CD) patients, and clinical observations revealed bacterial biofilms associated with the mucosa of CD patients. Here, analysis of the σEregulon in AIEC and commensalE. coliidentified 12 genes controlled by σEonly in AIEC. Among them, WaaWVL factors were found to play an essential role in biofilm formation and mucosal colonization by AIEC. In addition to identifying molecular tools that revealed a pathogenic population ofE. colicolonizing the mucosa of CD patients, these results indicate that targeting thewaaWVLoperon could be a potent therapeutic strategy to interfere with the ability of AIEC to form biofilms and to colonize the gut mucosa.

scholarly journals Adherent-Invasive E. coli: Update on the Lifestyle of a Troublemaker in Crohn’s Disease

2020 ◽  
Vol 21 (10) ◽  
pp. 3734 ◽  
Author(s):  
Mélissa Chervy ◽  
Nicolas Barnich ◽  
Jérémy Denizot
Keyword(s):  
Escherichia Coli ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Genetic Factors ◽  
Intestinal Epithelial Cells ◽  
Intestinal Lumen ◽  
Intestinal Epithelial ◽  
E Coli ◽  
The Subject ◽  
The Impact

Besides genetic polymorphisms and environmental factors, the intestinal microbiota is an important factor in the etiology of Crohn’s disease (CD). Among microbiota alterations, a particular pathotype of Escherichia coli involved in the pathogenesis of CD abnormally colonizes the intestinal mucosa of patients: the adherent-invasive Escherichia coli (AIEC) pathobiont bacteria, which have the abilities to adhere to and to invade intestinal epithelial cells (IECs), as well as to survive and replicate within macrophages. AIEC have been the subject of many studies in recent years to unveil some genes linked to AIEC virulence and to understand the impact of AIEC infection on the gut and consequently their involvement in CD. In this review, we describe the lifestyle of AIEC bacteria within the intestine, from the interaction with intestinal epithelial and immune cells with an emphasis on environmental and genetic factors favoring their implantation, to their lifestyle in the intestinal lumen. Finally, we discuss AIEC-targeting strategies such as the use of FimH antagonists, bacteriophages, or antibiotics, which could constitute therapeutic options to prevent and limit AIEC colonization in CD patients.

scholarly journals Development of Heptylmannoside-Based Glycoconjugate Antiadhesive Compounds against Adherent-Invasive Escherichia coli Bacteria Associated with Crohn's Disease

mBio ◽  
2015 ◽  
Vol 6 (6) ◽  
Author(s):  
Adeline Sivignon ◽  
Xibo Yan ◽  
Dimitri Alvarez Dorta ◽  
Richard Bonnet ◽  
Julie Bouckaert ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Intestinal Inflammation ◽  
Intestinal Epithelial ◽  
Content Type ◽  
Type 1 Pili

ABSTRACTThe ileal lesions of Crohn's disease (CD) patients are colonized by adherent-invasiveEscherichia coli(AIEC) bacteria. These bacteria adhere to mannose residues expressed by CEACAM6 on host cells in a type 1 pilus-dependent manner. In this study, we investigated different antagonists of FimH, the adhesin of type 1 pili, for their ability to block AIEC adhesion to intestinal epithelial cells (IEC). Monovalent and multivalent derivatives ofn-heptyl α-d-mannoside (HM), a nanomolar antagonist of FimH, were testedin vitroin IEC infected with the AIEC LF82 strain andin vivoby oral administration to CEACAM6-expressing mice infected with LF82 bacteria.In vitro, multivalent derivatives were more potent than the monovalent derivatives, with a gain of efficacy superior to their valencies, probably owing to their ability to form bacterial aggregates. Of note, HM and the multi-HM glycoconjugates exhibited lower efficacyin vivoin decreasing LF82 gut colonization. Interestingly, HM analogues functionalized with an isopropylamide (1A-HM) or β-cyclodextrin pharmacophore at the end of the heptyl tail (1CD-HM) exerted beneficial effectsin vivo. These two compounds strongly decreased the amount of LF82 bacteria in the feces of mice and that of bacteria associated with the gut mucosa when administered orally at a dose of 10 mg/kg of body weight after infection. Importantly, signs of colitis and intestinal inflammation induced by LF82 infection were also prevented. These results highlight the potential of the antiadhesive compounds to treat CD patients abnormally colonized by AIEC bacteria and point to an alternative to the current approach focusing on blocking proinflammatory mediators.IMPORTANCECurrent treatments for Crohn's disease (CD), including immunosuppressive agents, anti-tumor necrosis factor alpha (anti-TNF-α) and anti-integrin antibodies, focus on the symptoms but not on the cause of the disease. Adherent-invasiveEscherichia coli(AIEC) bacteria abnormally colonize the ileal mucosa of CD patients via the interaction of the mannose-specific adhesin FimH of type 1 pili with CEACAM6 mannosylated proteins expressed on the epithelial cell surface. Thus, we decided to develop an antiadhesive strategy based on synthetic FimH antagonists specifically targeting AIEC bacteria that would decrease intestinal inflammation. Heptylmannoside (HM)-based glycocompounds strongly inhibit AIEC adhesion to intestinal epithelial cellsin vitro. The antiadhesive effect of two of these compounds of relatively simple chemical structure was also observedin vivoin AIEC-infected CEACAM6-expressing mice and was associated with a reduction in the signs of colitis. These results suggest a new therapeutic approach for CD patients colonized by AIEC bacteria, based on the development of synthetic FimH antagonists.

scholarly journals Adherent-Invasive Escherichia coli Phenotype Displayed by Intestinal Pathogenic E. coli Strains from Cats, Dogs, and Swine

2011 ◽  
Vol 77 (16) ◽  
pp. 5813-5817 ◽  
Author(s):  
Margarita Martinez-Medina ◽  
Jesus Garcia-Gil ◽  
Nicolas Barnich ◽  
Lothar H. Wieler ◽  
Christa Ewers
Keyword(s):  
Escherichia Coli ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Virulence Gene ◽  
Content Type ◽  
E Coli ◽  
Gene Profiles ◽  
Putative Role ◽  
Phylogenetic Origin ◽  
Disease Specificity

ABSTRACTThe adherent-invasiveEscherichia coli(AIEC) pathotype, which has been associated with Crohn's disease, shows similar traits to human and animal extraintestinal pathogenicE. coli(ExPEC) with respect to their phylogenetic origin and virulence gene profiles. Here, we demonstrate that animal ExPEC strains generally do not share the AIEC phenotype. In contrast, this phenotype is very frequent among animal intestinal pathogenicE. coli(InPEC) strains, particularly of feline and canine origin, that genetically resemble ExPEC. These results strengthen the particular identity and disease specificity of the AIEC pathotype and the putative role animals might play in the transmission of AIEC-like strains to humans.

PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation

Microbiology ◽  
2021 ◽  
Vol 167 (3) ◽  
Author(s):  
Sathi Mallick ◽  
Shanti Kiran ◽  
Tapas Kumar Maiti ◽  
Anindya S. Ghosh
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Type Species ◽  
Pentose Phosphate ◽  
Bacterial Cells ◽  
Surface Adhesion ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Link Type

Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.

scholarly journals Bioinformatic and Molecular Analysis of Inverse Autotransporters from Escherichia coli

mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Kelvin G. K. Goh ◽  
Danilo G. Moriel ◽  
Steven J. Hancock ◽  
Minh-Duy Phan ◽  
Mark A. Schembri
Keyword(s):  
Escherichia Coli ◽  
Cell Surface ◽  
Biofilm Formation ◽  
Secretion System ◽  
Content Type ◽  
E Coli ◽  
Wide Range ◽  
Type V Secretion ◽  
K 12 ◽  
Type V

ABSTRACT Proteins secreted by the type V secretion system possess multiple functions, including the capacity to mediate adhesion, aggregation, and biolfilm formation. The type V secretion system can be divided into five subclasses, one of which is the type Ve system. Proteins of the type Ve secretion system are also referred to as inverse autotransporters (IATs). In this study, we performed an in silico analysis of 126 completely sequenced Escherichia coli genomes available in the NCBI database and identified several distinct IAT-encoding gene families whose distribution varied throughout the E. coli phylogeny. The genes included three characterized IATs (intimin, fdeC, and yeeJ) and four uncharacterized IATs (here named iatA, iatB, iatC, and iatD). The four iat genes were cloned from the completely sequenced environmental E. coli strain SMS-3-5 and characterized. Three of these IAT proteins (IatB, IatC, and IatD) were expressed at the cell surface and possessed the capacity to mediate biofilm formation in a recombinant E. coli K-12 strain. Further analysis of the iatB gene, which showed a unique association with extraintestinal E. coli strains, suggested that its regulation is controlled by the LeuO global regulator. Overall, this study provides new data describing the prevalence, sequence variation, domain structure, function, and regulation of IATs found in E. coli. IMPORTANCE Escherichia coli is one of the most prevalent facultative anaerobes of the human gut. E. coli normally exists as a harmless commensal but can also cause disease following the acquisition of genes that enhance its pathogenicity. Adhesion is an important first step in colonization of the host and is mediated by an array of cell surface components. In E. coli, these include a family of adhesins secreted by the type V secretion system. Here, we identified and characterized new proteins from an emerging subclass of the type V secretion system known as the inverse autotransporters (IATs). We found that IAT-encoding genes are present in a wide range of strains and showed that three novel IATs were localized on the E. coli cell surface and mediated biofilm formation. Overall, this study provides new insight into the prevalence, function, and regulation of IATs in E. coli.

scholarly journals Invasive Ability of an Escherichia coliStrain Isolated from the Ileal Mucosa of a Patient with Crohn’s Disease

1999 ◽  
Vol 67 (9) ◽  
pp. 4499-4509 ◽  
Author(s):  
Jerome Boudeau ◽  
Anne-Lise Glasser ◽  
Estelle Masseret ◽  
Bernard Joly ◽  
Arlette Darfeuille-Michaud
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Host Cell ◽  
Bacterial Invasion ◽  
Intestinal Epithelial ◽  
Invasive Ability ◽  
Ileal Mucosa ◽  
Gastrointestinal Infections ◽  
E Coli ◽  
Host Cell Membranes

ABSTRACT Crohn’s disease (CD) is an inflammatory bowel disease in whichEscherichia coli strains have been suspected of being involved. We demonstrated previously that ileal lesions of CD are colonized by E. coli strains able to adhere to intestinal Caco-2 cells but devoid of the virulence genes so far described in the pathogenic E. coli strains involved in gastrointestinal infections. In the present study we compared the invasive ability of one of these strains isolated from an ileal biopsy of a patient with CD, strain LF82, with that of reference enteroinvasive (EIEC), enteropathogenic (EPEC), enterotoxigenic (ETEC), enteraggregative (EAggEC), enterohemorrhagic (EHEC), and diffusely adhering (DAEC)E. coli strains. Gentamicin protection assays showed thatE. coli LF82 was able to efficiently invade HEp-2 cells. Its invasive level was not significantly different from that of EIEC and EPEC strains (P > 0.5) but significantly higher than that of ETEC (P < 0.03), EHEC (P < 0.005), EAggEC (P < 0.004) and DAEC (P < 0.02) strains. Strain LF82 also demonstrated efficient ability to invade intestinal epithelial cultured Caco-2, Intestine-407, and HCT-8 cells. Electron microscopy examination of infected HEp-2 cells revealed the presence of numerous intracellular bacteria located in vacuoles or free in the host cell cytoplasm. In addition, the interaction of strain LF82 with epithelial cells was associated with the elongation of microvillar extensions that extruded from the host cell membranes and engulfed the bacteria. This internalization mechanism strongly resembles Salmonella- orShigella-induced macropinocytosis. The use of cytochalasin D and colchicine showed that the uptake of strain LF82 by HEp-2 cells was mediated by both an actin microfilament-dependent mechanism and microtubule involvement. In addition, strain LF82 survived for at least 24 h in HEp-2 and Intestine-407 cells and efficiently replicated intracellularly in HEp-2 cells. PCR and hybridization experiments did not reveal the presence of any of the genetic determinants encoding EIEC, EPEC, or ETEC proteins involved in bacterial invasion. Thus, these findings show that LF82, which colonized the ileal mucosa of a patient with CD, is a true invasive E. coli strain and suggest the existence of a new potentially pathogenic group of E. coli, which we propose be designated adherent-invasive E. coli.

scholarly journals Flagellum-Mediated Mechanosensing and RflP Control Motility State of Pathogenic Escherichia coli

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Leanid Laganenka ◽  
María Esteban López ◽  
Remy Colin ◽  
Victor Sourjik
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Porous Medium ◽  
Biofilm Formation ◽  
Liquid Culture ◽  
Content Type ◽  
E Coli ◽  
Surface Contact ◽  
Conditional Inhibition ◽  
Flagellar Genes

ABSTRACT Bacterial flagellar motility plays an important role in many processes that occur at surfaces or in hydrogels, including adhesion, biofilm formation, and bacterium-host interactions. Consequently, expression of flagellar genes, as well as genes involved in biofilm formation and virulence, can be regulated by the surface contact. In a few bacterial species, flagella themselves are known to serve as mechanosensors, where an increased load on flagella experienced during surface contact or swimming in viscous media controls gene expression. In this study, we show that gene regulation by motility-dependent mechanosensing is common among pathogenic Escherichia coli strains. This regulatory mechanism requires flagellar rotation, and it enables pathogenic E. coli to repress flagellar genes at low loads in liquid culture, while activating motility in porous medium (soft agar) or upon surface contact. It also controls several other cellular functions, including metabolism and signaling. The mechanosensing response in pathogenic E. coli depends on the negative regulator of motility, RflP (YdiV), which inhibits basal expression of flagellar genes in liquid. While no conditional inhibition of flagellar gene expression in liquid and therefore no upregulation in porous medium was observed in the wild-type commensal or laboratory strains of E. coli, mechanosensitive regulation could be recovered by overexpression of RflP in the laboratory strain. We hypothesize that this conditional activation of flagellar genes in pathogenic E. coli reflects adaptation to the dual role played by flagella and motility during infection. IMPORTANCE Flagella and motility are widespread virulence factors among pathogenic bacteria. Motility enhances the initial host colonization, but the flagellum is a major antigen targeted by the host immune system. Here, we demonstrate that pathogenic E. coli strains employ a mechanosensory function of the flagellar motor to activate flagellar expression under high loads, while repressing it in liquid culture. We hypothesize that this mechanism allows pathogenic E. coli to regulate its motility dependent on the stage of infection, activating flagellar expression upon initial contact with the host epithelium, when motility is beneficial, but reducing it within the host to delay the immune response.

scholarly journals Inflammation-Induced Acid Tolerance GenesgadABin Luminal Commensal Escherichia coli Attenuate Experimental Colitis

2013 ◽  
Vol 81 (10) ◽  
pp. 3662-3671 ◽  
Author(s):  
Sandrine Tchaptchet ◽  
Ting-Jia Fan ◽  
Laura Goeser ◽  
Alexi Schoenborn ◽  
Ajay S. Gulati ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Immune Responses ◽  
Intestinal Inflammation ◽  
Intestinal Epithelial Cells ◽  
Acid Tolerance ◽  
Experimental Colitis ◽  
Intestinal Epithelial ◽  
Content Type ◽  
E Coli ◽  
Chronic Intestinal Inflammation

ABSTRACTDysregulated immune responses to commensal intestinal bacteria, includingEscherichia coli, contribute to the development of inflammatory bowel diseases (IBDs) and experimental colitis. Reciprocally,E. coliresponds to chronic intestinal inflammation by upregulating expression of stress response genes, includinggadAandgadB. GadAB encode glutamate decarboxylase and protectE. colifrom the toxic effects of low pH and fermentation acids, factors present in the intestinal lumen in patients with active IBDs. We hypothesized thatE. coliupregulatesgadABduring inflammation to enhance its survival and virulence. Using real-time PCR, we determinedgadABexpression in luminalE. colifrom ex-germfree wild-type (WT) and interleukin-10 (IL-10) knockout (KO) (IL-10−/−) mice selectively colonized with a commensalE. coliisolate (NC101) that causes colitis in KO mice in isolation or in combination with 7 other commensal intestinal bacterial strains.E. colisurvival and host inflammatory responses were measured in WT and KO mice colonized with NC101 or a mutant lacking thegadABgenes (NC101ΔgadAB). The susceptibility of NC101 and NC101ΔgadABto killing by host antimicrobial peptides and their translocation across intestinal epithelial cells were evaluated using bacterial killing assays and transwell experiments, respectively. We show that expression ofgadABin luminalE. coliincreases proportionately with intestinal inflammation in KO mice and enhances the susceptibility of NC101 to killing by the host antimicrobial peptide cryptdin-4 but decreases bacterial transmigration across intestinal epithelial cells, colonic inflammation, and mucosal immune responses. Chronic intestinal inflammation upregulates acid tolerance pathways in commensalE. coliisolates, which, contrary to our original hypothesis, limits their survival and colitogenic potential. Further investigation of microbial adaptation to immune-mediated inflammation may provide novel insights into the pathogenesis and treatment of IBDs.

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