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Smith EM, Grassel CL, Papadimas A, Foulke-Abel J, Barry EM. The role of CFA/I in adherence and toxin delivery by ETEC expressing multiple colonization factors in the human enteroid model. PLoS Negl Trop Dis 2022; 16:e0010638. [PMID: 35881640 PMCID: PMC9355178 DOI: 10.1371/journal.pntd.0010638] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/05/2022] [Accepted: 07/07/2022] [Indexed: 01/10/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is a primary causative agent of diarrhea in travelers and young children in low-to-middle-income countries (LMICs). ETEC adhere to intestinal epithelia via colonization factors (CFs) and secrete heat-stable toxin (ST) and/or heat-labile toxin (LT), causing dysregulated cellular ion transport and water secretion. ETEC isolates often harbor genes encoding more than one CF that are targets as vaccine antigens. CFA/I is a major CF that is associated with ETEC that causes moderate-to-severe diarrhea and plays an important role in pathogenesis. The Global Enteric Multicenter Study finding that 78% of CFA/I-expressing ETEC also encode the minor CF CS21 prompted investigation of the combined role of these two CFs. Western blots and electron microscopy demonstrated growth media-dependent and strain-dependent differences in CFA/I and CS21 expression. The critical role of CFA/I in adherence by ETEC strains expressing CFA/I and CS21 was demonstrated using the human enteroid model and a series of CFA/I- and CS21-specific mutants. Furthermore, only anti-CFA/I antibodies inhibited adherence by global ETEC isolates expressing CFA/I and CS21. Delivery of ST and resulting cGMP secretion was measured in supernatants from infected enteroid monolayers, and strain-specific ST delivery and time-dependent cGMP production was observed. Interestingly, cGMP levels were similar across wildtype and CF-deficient strains, reflecting a limitation of this static aerobic infection model. Despite adherence by ETEC and delivery of ST, the enteroid monolayer integrity was not disrupted, as shown by the lack of decrease in transepithelial electrical resistance and the lack of IL-8 cytokines produced during infection. Taken together, these data demonstrate that targeting CFA/I in global clinical CFA/I-CS21 strains is sufficient for adherence inhibition, supporting a vaccine strategy that focuses on blocking major CFs. In addition, the human enteroid model has significant utility for the study of ETEC pathogenesis and evaluation of vaccine-induced functional antibody responses.
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Affiliation(s)
- Emily M. Smith
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Christen L. Grassel
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Antonia Papadimas
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jennifer Foulke-Abel
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Eileen M. Barry
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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Sauvaitre T, Durif C, Sivignon A, Chalancon S, Van de Wiele T, Etienne-Mesmin L, Blanquet-Diot S. In Vitro Evaluation of Dietary Fiber Anti-Infectious Properties against Food-Borne Enterotoxigenic Escherichia coli. Nutrients 2021; 13:nu13093188. [PMID: 34579065 PMCID: PMC8471546 DOI: 10.3390/nu13093188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/27/2021] [Accepted: 09/11/2021] [Indexed: 01/19/2023] Open
Abstract
Dietary fibers have well-known beneficial effects on human health, but their anti-infectious properties against human enteric pathogens have been poorly investigated. Enterotoxigenic Escherichia coli (ETEC) is the main agent of travelers’ diarrhea, against which targeted preventive strategies are currently lacking. ETEC pathogenesis relies on multiple virulence factors allowing interactions with the intestinal mucosal layer and toxins triggering the onset of diarrheal symptoms. Here, we used complementary in vitro assays to study the antagonistic properties of eight fiber-containing products from cereals, legumes or microbes against the prototypical human ETEC strain H10407. Inhibitory effects of these products on the pathogen were tested through growth, toxin production and mucus/cell adhesion inhibition assays. None of the tested compounds inhibited ETEC strain H10407 growth, while lentil extract was able to decrease heat labile toxin (LT) concentration in culture media. Lentil extract and specific yeast cell walls also interfered with ETEC strain H10407 adhesion to mucin beads and human intestinal cells. These results constitute a first step in the use of dietary fibers as a nutritional strategy to prevent ETEC infection. Further work will be dedicated to the study of fiber/ETEC interactions within a complex gut microbial background.
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Affiliation(s)
- Thomas Sauvaitre
- UMR 454 UCA-INRAE Microbiologie Environnement DIgestif et Santé (MEDIS), Université Clermont Auvergne, 63000 Clermont-Ferrand, France; (T.S.); (C.D.); (S.C.); (L.E.-M.)
- Faculty of Bioscience Engineering Center for Microbial Ecology and Technology (CMET), Ghent University, 9000 Ghent, Belgium;
| | - Claude Durif
- UMR 454 UCA-INRAE Microbiologie Environnement DIgestif et Santé (MEDIS), Université Clermont Auvergne, 63000 Clermont-Ferrand, France; (T.S.); (C.D.); (S.C.); (L.E.-M.)
| | - Adeline Sivignon
- UMR 1071 UCA Inserm USC-INRAE 2018 Microbes Intestin Inflammation et Susceptibilité de l’Hôte (M2iSH), Université Clermont Auvergne, 63000 Clermont-Ferrand, France;
| | - Sandrine Chalancon
- UMR 454 UCA-INRAE Microbiologie Environnement DIgestif et Santé (MEDIS), Université Clermont Auvergne, 63000 Clermont-Ferrand, France; (T.S.); (C.D.); (S.C.); (L.E.-M.)
| | - Tom Van de Wiele
- Faculty of Bioscience Engineering Center for Microbial Ecology and Technology (CMET), Ghent University, 9000 Ghent, Belgium;
| | - Lucie Etienne-Mesmin
- UMR 454 UCA-INRAE Microbiologie Environnement DIgestif et Santé (MEDIS), Université Clermont Auvergne, 63000 Clermont-Ferrand, France; (T.S.); (C.D.); (S.C.); (L.E.-M.)
| | - Stéphanie Blanquet-Diot
- UMR 454 UCA-INRAE Microbiologie Environnement DIgestif et Santé (MEDIS), Université Clermont Auvergne, 63000 Clermont-Ferrand, France; (T.S.); (C.D.); (S.C.); (L.E.-M.)
- Correspondence: ; Tel.: +33-473-178-390
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Abd El Ghany M, Barquist L, Clare S, Brandt C, Mayho M, Joffre´ E, Sjöling Å, Turner AK, Klena JD, Kingsley RA, Hill-Cawthorne GA, Dougan G, Pickard D. Functional analysis of colonization factor antigen I positive enterotoxigenic Escherichia coli identifies genes implicated in survival in water and host colonization. Microb Genom 2021; 7:000554. [PMID: 34110281 PMCID: PMC8461466 DOI: 10.1099/mgen.0.000554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/09/2021] [Indexed: 12/13/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) expressing the colonization pili CFA/I are common causes of diarrhoeal infections in humans. Here, we use a combination of transposon mutagenesis and transcriptomic analysis to identify genes and pathways that contribute to ETEC persistence in water environments and colonization of a mammalian host. ETEC persisting in water exhibit a distinct RNA expression profile from those growing in richer media. Multiple pathways were identified that contribute to water survival, including lipopolysaccharide biosynthesis and stress response regulons. The analysis also indicated that ETEC growing in vivo in mice encounter a bottleneck driving down the diversity of colonizing ETEC populations.
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Affiliation(s)
- Moataz Abd El Ghany
- The Westmead Institute for Medical Research, University of Sydney, Sydney, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, Australia
- The Westmead Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
- King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
- Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Simon Clare
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Cordelia Brandt
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Matthew Mayho
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Enrique Joffre´
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Åsa Sjöling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - A. Keith Turner
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - John D. Klena
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Robert A. Kingsley
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | | | - Gordon Dougan
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Derek Pickard
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
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Von Mentzer A, Zalem D, Chrienova Z, Teneberg S. Colonization factor CS30 from enterotoxigenic Escherichia coli binds to sulfatide in human and porcine small intestine. Virulence 2021; 11:381-390. [PMID: 32245341 PMCID: PMC7161690 DOI: 10.1080/21505594.2020.1749497] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The ability to adhere via colonization factors to specific receptors located on the intestinal mucosa is a key virulence factor in enterotoxigenic Escherichia coli (ETEC) pathogenesis. Here, the potential glycosphingolipid receptors of the novel human ETEC colonization factor CS30 were examined by binding of CS30-expressing bacteria to glycosphingolipids on thin-layer chromatograms. We thereby found a highly specific binding of CS30-expressing bacteria to a fast-migrating acid glycosphingolipid of human and porcine small intestine, while no binding was obtained with a mutant ETEC strain unable to express CS30 fimbriae. The CS30 binding glycosphingolipid from human small intestine was isolated and characterized by mass spectrometry as sulfatide (SO3-3Galβ1Cer). Comparative binding studies using sulfatides with different ceramide compositions gave a preferential binding of CS30 to sulfatide with d18:1-h24:0 ceramide. This ceramide species of sulfatide was also isolated from human small intestine and characterized by mass spectrometry and antibody binding. These studies implicate sulfatide as candidate receptor for mediating attachment of CS30-fimbriated ETEC to human and porcine small intestinal cells. Our findings may be a basis for designing receptor saccharide analogues for inhibition of the intestinal adhesion of CS30-expressing E. coli.
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Affiliation(s)
- Astrid Von Mentzer
- Department of Microbiology and Immunology, Sahlgrenska Academy, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.,Wellcome Sanger Institute: Parasites and Microbes Programme, Hinxton, UK
| | - Dani Zalem
- Department of Medical Biochemistry and Cell Biology, Sahlgrenska Academy, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Zofia Chrienova
- Department of Medical Biochemistry and Cell Biology, Sahlgrenska Academy, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.,Department of Chemistry, Faculty of Science, University of Hradec Králové, Hradec Králové, Czech Republic
| | - Susann Teneberg
- Department of Medical Biochemistry and Cell Biology, Sahlgrenska Academy, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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Glyco-engineered cell line and computational docking studies reveals enterotoxigenic Escherichia coli CFA/I fimbriae bind to Lewis a glycans. Sci Rep 2018; 8:11250. [PMID: 30050155 PMCID: PMC6062558 DOI: 10.1038/s41598-018-29258-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 07/09/2018] [Indexed: 12/16/2022] Open
Abstract
We have previously reported clinical data to suggest that colonization factor I (CFA/I) fimbriae of enterotoxigenic Escherichia coli (ETEC) can bind to Lewis a (Lea), a glycan epitope ubiquitous in the small intestinal mucosa of young children (<2 years of age), and individuals with a genetic mutation of FUT2. To further elucidate the physiological binding properties of this interaction, we engineered Chinese Hamster Ovary (CHO-K1) cells to express Lea or Leb determinants on both N- and O-glycans. We used our glyco-engineered CHO-K1 cell lines to demonstrate that CfaB, the major subunit of ETEC CFA/I fimbriae, as well as four related ETEC fimbriae, bind more to our CHO-K1 cell-line expressing Lea, compared to cells carrying Leb or the CHO-K1 wild-type glycan phenotype. Furthermore, using in-silico docking analysis, we predict up to three amino acids (Glu25, Asn27, Thr29) found in the immunoglobulin (Ig)-like groove region of CfaB of CFA/I and related fimbriae, could be important for the preferential and higher affinity binding of CFA/I fimbriae to the potentially structurally flexible Lea glycan. These findings may lead to a better molecular understanding of ETEC pathogenesis, aiding in the development of vaccines and/or anti-infection therapeutics.
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Interplay of a secreted protein with type IVb pilus for efficient enterotoxigenic Escherichia coli colonization. Proc Natl Acad Sci U S A 2018; 115:7422-7427. [PMID: 29941571 PMCID: PMC6048534 DOI: 10.1073/pnas.1805671115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To avoid the mucosal barrier and attach to the intestinal epithelium, enteric pathogens have evolved a unique proteinaceous fiber called type IVb pilus (T4bP). Despite its importance for bacterial pathogenesis, little is known about the adhesion mechanisms of T4bP, especially regarding the role of the minor pilin subunit located at its tip. Here, we show that the type IVb minor pilin CofB of CFA/III from enterotoxigenic Escherichia coli (ETEC) plays a role not only in T4bP assembly by forming a trimeric initiator complex, but also in bacterial adhesion by anchoring a secreted protein, CofJ, at the trimerization interface of H-type lectin domain. These findings expand our knowledge of T4P biology and provide important insights for developing therapeutics against ETEC infection. Initial attachment and subsequent colonization of the intestinal epithelium comprise critical events allowing enteric pathogens to survive and express their pathogenesis. In enterotoxigenic Escherichia coli (ETEC), these are mediated by a long proteinaceous fiber termed type IVb pilus (T4bP). We have reported that the colonization factor antigen/III (CFA/III), an operon-encoded T4bP of ETEC, possesses a minor pilin, CofB, that carries an H-type lectin domain at its tip. Although CofB is critical for pilus assembly by forming a trimeric initiator complex, its importance for bacterial attachment remains undefined. Here, we show that T4bP is not sufficient for bacterial attachment, which also requires a secreted protein CofJ, encoded within the same CFA/III operon. The crystal structure of CofB complexed with a peptide encompassing the binding region of CofJ showed that CofJ interacts with CofB by anchoring its flexible N-terminal extension to be embedded deeply into the expected carbohydrate recognition site of the CofB H-type lectin domain. By combining this structure and physicochemical data in solution, we built a plausible model of the CofJ–CFA/III pilus complex, which suggested that CofJ acts as a molecular bridge by binding both T4bP and the host cell membrane. The Fab fragments of a polyclonal antibody against CofJ significantly inhibited bacterial attachment by preventing the adherence of secreted CofJ proteins. These findings signify the interplay between T4bP and a secreted protein for attaching to and colonizing the host cell surface, potentially constituting a therapeutic target against ETEC infection.
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Sheikh A, Rashu R, Begum YA, Kuhlman FM, Ciorba MA, Hultgren SJ, Qadri F, Fleckenstein JM. Highly conserved type 1 pili promote enterotoxigenic E. coli pathogen-host interactions. PLoS Negl Trop Dis 2017; 11:e0005586. [PMID: 28531220 PMCID: PMC5456409 DOI: 10.1371/journal.pntd.0005586] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/02/2017] [Accepted: 04/21/2017] [Indexed: 12/22/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC), defined by their elaboration of heat-labile (LT) and/or heat-stable (ST) enterotoxins, are a common cause of diarrheal illness in developing countries. Efficient delivery of these toxins requires ETEC to engage target host enterocytes. This engagement is accomplished using a variety of pathovar-specific and conserved E. coli adhesin molecules as well as plasmid encoded colonization factors. Some of these adhesins undergo significant transcriptional modulation as ETEC encounter intestinal epithelia, perhaps suggesting that they cooperatively facilitate interaction with the host. Among genes significantly upregulated on cell contact are those encoding type 1 pili. We therefore investigated the role played by these pili in facilitating ETEC adhesion, and toxin delivery to model intestinal epithelia. We demonstrate that type 1 pili, encoded in the E. coli core genome, play an essential role in ETEC virulence, acting in concert with plasmid-encoded pathovar specific colonization factor (CF) fimbriae to promote optimal bacterial adhesion to cultured intestinal epithelium (CIE) and to epithelial monolayers differentiated from human small intestinal stem cells. Type 1 pili are tipped with the FimH adhesin which recognizes mannose with stereochemical specificity. Thus, enhanced production of highly mannosylated proteins on intestinal epithelia promoted FimH-mediated ETEC adhesion, while conversely, interruption of FimH lectin-epithelial interactions with soluble mannose, anti-FimH antibodies or mutagenesis of fimH effectively blocked ETEC adhesion. Moreover, fimH mutants were significantly impaired in delivery of both heat-stable and heat-labile toxins to the target epithelial cells in vitro, and these mutants were substantially less virulent in rabbit ileal loop assays, a classical model of ETEC pathogenesis. Collectively, our data suggest that these highly conserved pili play an essential role in virulence of these diverse pathogens.
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Affiliation(s)
- Alaullah Sheikh
- Molecular Microbiology and Microbial Pathogenesis Program, Division of Biology and Biomedical Sciences, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Rasheduzzaman Rashu
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddrb), Mohakhali, Dhaka, Bangladesh
| | - Yasmin Ara Begum
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddrb), Mohakhali, Dhaka, Bangladesh
| | - F. Matthew Kuhlman
- Division of Infectious Disease, Department of Internal Medicine, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Matthew A. Ciorba
- Division of Gastroenterology, Department of Internal Medicine, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Scott J. Hultgren
- Department of Molecular Microbiology, Washington University in Saint Louis, Saint Louis, Missouri, United States of America
- Center for Women’s Infectious Disease Research (CWIDR), Washington University in Saint Louis, Saint Louis, Missouri, United States of America
| | - Firdausi Qadri
- Infectious Diseases Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddrb), Mohakhali, Dhaka, Bangladesh
| | - James M. Fleckenstein
- Molecular Microbiology and Microbial Pathogenesis Program, Division of Biology and Biomedical Sciences, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Division of Infectious Disease, Department of Internal Medicine, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- Medicine Service, Veterans Affairs Medical Center, Saint Louis, Missouri, United States of America
- * E-mail:
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