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Subramanian DA, Langer R, Traverso G. Mucus interaction to improve gastrointestinal retention and pharmacokinetics of orally administered nano-drug delivery systems. J Nanobiotechnology 2022; 20:362. [PMID: 35933341 PMCID: PMC9356434 DOI: 10.1186/s12951-022-01539-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/27/2022] [Indexed: 11/29/2022] Open
Abstract
Oral delivery of therapeutics is the preferred route of administration due to ease of administration which is associated with greater patient medication adherence. One major barrier to oral delivery and intestinal absorption is rapid clearance of the drug and the drug delivery system from the gastrointestinal (GI) tract. To address this issue, researchers have investigated using GI mucus to help maximize the pharmacokinetics of the therapeutic; while mucus can act as a barrier to effective oral delivery, it can also be used as an anchoring mechanism to improve intestinal residence. Nano-drug delivery systems that use materials which can interact with the mucus layers in the GI tract can enable longer residence time, improving the efficacy of oral drug delivery. This review examines the properties and function of mucus in the GI tract, as well as diseases that alter mucus. Three broad classes of mucus-interacting systems are discussed: mucoadhesive, mucus-penetrating, and mucolytic drug delivery systems. For each class of system, the basis for mucus interaction is presented, and examples of materials that inform the development of these systems are discussed and reviewed. Finally, a list of FDA-approved mucoadhesive, mucus-penetrating, and mucolytic drug delivery systems is reviewed. In summary, this review highlights the progress made in developing mucus-interacting systems, both at a research-scale and commercial-scale level, and describes the theoretical basis for each type of system.
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Affiliation(s)
- Deepak A Subramanian
- Department of Chemical Engineering and David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Robert Langer
- Department of Chemical Engineering and David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Giovanni Traverso
- Department of Chemical Engineering and David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Division of Gastroenterology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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Wen X, Zhong R, Dang G, Xia B, Wu W, Tang S, Tang L, Liu L, Liu Z, Chen L, Zhang H. Pectin supplementation ameliorates intestinal epithelial barrier function damage by modulating intestinal microbiota in lipopolysaccharide-challenged piglets. J Nutr Biochem 2022; 109:109107. [PMID: 35863585 DOI: 10.1016/j.jnutbio.2022.109107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 12/01/2022]
Abstract
During weaning, infants and young animals are susceptible to severe enteric infections, thus inducing intestinal microbiota dysbiosis, intestinal inflammation, and impaired intestinal barrier function. Pectin (PEC), a prebiotic polysaccharide, enhances intestinal health with the potential for therapeutic effect on intestinal diseases. One 21-days study was conducted to investigate the protective effect of pectin against intestinal injury induced by intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS) in a piglet model. A total of 24 piglets (6.77±0.92 kg BW; Duroc × Landrace × Large White; barrows; 21 d of age) were randomly assigned into three groups: control group, LPS-challenged group, and PEC + LPS group. Piglets were administrated with LPS or saline on d14 and d21 of the experiment. All piglets were slaughtered and intestinal samples were collected after 3 h administration on d21. Pectin supplementation ameliorated the LPS-induced inflammation response and damage to the ileal morphology. Meanwhile, pectin also improved intestinal mucin barrier function, increased the mRNA expression of MUC2, and improved intestinal mucus glycosylation. LPS challenge reduced the diversity of intestinal microbiota and enriched the relative abundance of Helicobacter. Pectin restored alpha diversity improved the structure of the gut microbiota by enriching anti-inflammatory bacteria and short-chain fatty acid (SCFA)-producing bacteria, and increased the concentrations of acetate. In addition, Spearman rank correlation analysis also revealed the potential relationship between intestinal microbiota and intestinal morphology, intestinal inflammation, and intestinal glycosylation in piglets. Taken together, these results indicate that pectin enhances intestinal integrity and barrier function by altering intestinal microbiota composition and their metabolites, which subsequently alleviates intestinal injury and finally improves the growth performance of piglets.
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Affiliation(s)
- Xiaobin Wen
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Ruqing Zhong
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Guoqi Dang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; Precision Livestock and Nutrition Unit, Gembloux Agro-Bio Tech, TERRA Teaching and Research Centre, Liège University, Passage des Déportés 2, Gembloux, 5030, Belgium
| | - Bing Xia
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Weida Wu
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Shanlong Tang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Lixin Tang
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Animal and Plant Sciences, Chinese Academy of Agricultural Sciences, Changchun, 130000, China
| | - Lei Liu
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Zhengqun Liu
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Liang Chen
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
| | - Hongfu Zhang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
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Dufresne K, Daigle F. Identification of Crp as a novel regulator of the Std fimbrial expression in Salmonella. MICROBIOLOGY-SGM 2021; 167. [PMID: 33475482 DOI: 10.1099/mic.0.001022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Salmonella enterica serovar Typhi genome contains 14 putative fimbrial systems. The Std fimbriae belong to the chaperone-usher family and its regulation has not been investigated in S. Typhi. Several regulators of Std were previously identified in the closely related serovar Typhimurium. We hypothesize that regulators of S. Typhimurium may be shared with S. Typhi, but that several other regulators remain to be discovered. Here, we describe the role of more than 50 different candidate regulators on std expression. Three types of regulators were investigated: known regulators in S. Typhimurium, in silico predicted regulators and virulence/metabolic regulators. Expression of std was determined in the regulator mutants and compared with the wild-type strain. Overall, 21 regulator mutations affect std promoter expression. The role of Crp, a newly identified factor for std expression, was further investigated. Crp acted as an activator of std expression on a distal region of the std promoter region. Together, our results demonstrate the major influence of Crp as a novel transcriptional factor on std promoter expression and later production of Std fimbriae in Salmonella.
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Affiliation(s)
- Karine Dufresne
- Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal (QC), H3T 1J4, Canada
| | - France Daigle
- Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal (QC), H3T 1J4, Canada
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García-Pastor L, Sánchez-Romero MA, Gutiérrez G, Puerta-Fernández E, Casadesús J. Formation of phenotypic lineages in Salmonella enterica by a pleiotropic fimbrial switch. PLoS Genet 2018; 14:e1007677. [PMID: 30252837 PMCID: PMC6173445 DOI: 10.1371/journal.pgen.1007677] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/05/2018] [Accepted: 09/05/2018] [Indexed: 11/29/2022] Open
Abstract
The std locus of Salmonella enterica, an operon acquired by horizontal transfer, encodes fimbriae that permit adhesion to epithelial cells in the large intestine. Expression of the std operon is bistable, yielding a major subpopulation of StdOFF cells (99.7%) and a minor subpopulation of StdON cells (0.3%). In addition to fimbrial proteins, the std operon encodes two proteins, StdE and StdF, that have DNA binding capacity and control transcription of loci involved in flagellar synthesis, chemotaxis, virulence, conjugal transfer, biofilm formation, and other cellular functions. As a consequence of StdEF pleiotropic transcriptional control, StdON and StdOFF subpopulations may differ not only in the presence or absence of Std fimbriae but also in additional phenotypic traits. Separation of StdOFF and StdON lineages by cell sorting confirms the occurrence of lineage-specific features. Formation of StdOFF and StdON lineages may thus be viewed as a rudimentary bacterial differentiation program. We show that the std fimbrial operon of Salmonella enterica undergoes bistable expression, a trait far from exceptional among loci that encode components of the bacterial envelope. However, an unsuspected trait of the std operon is the presence of two genes that encode pleiotropic regulators of gene expression. Indeed, StdE and StdF are DNA-binding proteins that control transcription of hundreds of genes. As a consequence, StdEF govern multiple phenotypic traits, and the fimbriated and non-fimbriated Salmonella lineages may differ in motility, virulence, conjugal transfer, biofilm formation, and potentially in other phenotypic features. We hypothesize that pleiotropic control of gene expression by StdEF may contribute to adapt the non-fimbriated lineage to acute infection and the fimbriated lineage to chronic infection.
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Affiliation(s)
- Lucía García-Pastor
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | | | - Gabriel Gutiérrez
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Elena Puerta-Fernández
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
- Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Sevilla, Spain
- * E-mail: (EPF); (JC)
| | - Josep Casadesús
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
- * E-mail: (EPF); (JC)
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García-Pastor L, Puerta-Fernández E, Casadesús J. Bistability and phase variation in Salmonella enterica. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:752-758. [PMID: 29369799 DOI: 10.1016/j.bbagrm.2018.01.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 01/09/2018] [Indexed: 11/18/2022]
Abstract
Cell-to-cell differences in bacterial gene expression can merely reflect the occurrence of noise. In certain cases, however, heterogeneous gene expression is a programmed event that results in bistable expression. If bistability is heritable, bacterial lineages are formed. When programmed bistability is reversible, the phenomenon is known as phase variation. In certain cases, bistability is controlled by genetic mechanisms (e. g., DNA rearrangement). In other cases, bistability has epigenetic origin. A robust epigenetic mechanism for the formation of bacterial lineages is the formation of heritable DNA methylation patterns. However, bistability can also arise upon propagation of gene expression patterns by feedback loops that are stable upon cell division. This review describes examples of bistability and phase variation in Salmonella enterica and discusses their adaptive value, sometimes in a speculative manner.
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Affiliation(s)
- Lucía García-Pastor
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain
| | - Elena Puerta-Fernández
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain
| | - Josep Casadesús
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain.
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Hansmeier N, Miskiewicz K, Elpers L, Liss V, Hensel M, Sterzenbach T. Functional expression of the entire adhesiome of Salmonella enterica serotype Typhimurium. Sci Rep 2017; 7:10326. [PMID: 28871183 PMCID: PMC5583245 DOI: 10.1038/s41598-017-10598-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/10/2017] [Indexed: 12/21/2022] Open
Abstract
Adhesins are crucial virulence factors of pathogenic bacteria involved in colonization, transmission and pathogenesis. Many bacterial genomes contain the information for a surprisingly large number of diverse adhesive structures. One prominent example is the invasive and facultative intracellular pathogen Salmonella enterica with an adhesiome of up to 20 adhesins. Such large repertoire of adhesins contributes to colonization of a broad range of host species and may allow adaptation to various environments within the host, as well as in non-host environments. For S. enterica, only few members of the adhesiome are functionally expressed under laboratory conditions, and accordingly the structural and functional understanding of the majority of adhesins is sparse. We have devised a simple and versatile approach to functionally express all adhesins of S. enterica serotype Typhimurium, either within Salmonella or within heterologous hosts such as Escherichia coli. We demonstrate the surface expression of various so far cryptic adhesins and show ultrastructural features using atomic force microscopy and transmission electron microscopy. In summary, we report for the first time the expression of the entire adhesiome of S. enterica serotype Typhimurium.
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Affiliation(s)
- Nicole Hansmeier
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, Barbarastr. 11, 49076, Osnabrück, Germany
| | - Katarzyna Miskiewicz
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, Barbarastr. 11, 49076, Osnabrück, Germany
| | - Laura Elpers
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, Barbarastr. 11, 49076, Osnabrück, Germany
| | - Viktoria Liss
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, Barbarastr. 11, 49076, Osnabrück, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, Barbarastr. 11, 49076, Osnabrück, Germany.
| | - Torsten Sterzenbach
- Abteilung Mikrobiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, Barbarastr. 11, 49076, Osnabrück, Germany.
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Goto Y, Uematsu S, Kiyono H. Epithelial glycosylation in gut homeostasis and inflammation. Nat Immunol 2016; 17:1244-1251. [PMID: 27760104 DOI: 10.1038/ni.3587] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intestinal epithelial cells apically express glycans, especially α1,2-fucosyl linkages, which work as a biological interface for the host-microbe interaction. Emerging studies have shown that epithelial α1,2-fucosylation is regulated by microbes and by group 3 innate lymphoid cells (ILC3s). Dysregulation of the gene (FUT2) encoding fucosyltransferase 2, an enzyme governing epithelial α1,2-fucosylation, is associated with various human disorders, including infection and chronic inflammatory diseases. This suggests a critical role for an interaction between microbes, epithelial cells and ILC3s mediated via glycan residues. In this Review, using α1,2-fucose and Fut2 gene expression as an example, we describe how epithelial glycosylation is controlled by immune cells and luminal microbes. We also address the pathophysiological contribution of epithelial α1,2-fucosylation to pathogenic and commensal microbes as well as the potential of α1,2-fucose and its regulatory pathway as previously unexploited targets in the development of new therapeutic approaches for human diseases.
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Affiliation(s)
- Yoshiyuki Goto
- Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, Chiba, Japan
- International Research and Development Center for Mucosal Vaccines, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Satoshi Uematsu
- International Research and Development Center for Mucosal Vaccines, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- Department of Mucosal Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Hiroshi Kiyono
- International Research and Development Center for Mucosal Vaccines, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
- Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan
- Division of Mucosal Immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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8
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Shanks RMQ, Stella NA, Brothers KM, Polaski DM. Exploitation of a "hockey-puck" phenotype to identify pilus and biofilm regulators in Serratia marcescens through genetic analysis. Can J Microbiol 2015; 62:83-93. [PMID: 26640000 DOI: 10.1139/cjm-2015-0566] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Pili are essential adhesive determinants for many bacterial pathogens. A suppressor mutation screen that takes advantage of a pilus-mediated self-aggregative "hockey-puck" colony phenotype was designed to identify novel regulators of type I pili in Serratia marcescens. Mutations that decreased pilus biosynthesis mapped to the fimABCD operon; to the genes alaT, fkpA, and oxyR; upstream of the flagellar master regulator operon flhDC; and to an uncharacterized gene encoding a predicted DUF1401 domain. Biofilm formation and pilus-dependent agglutination assays were used to characterize the relative importance of the identified genes in pilus biosynthesis. Additional mutagenic or complementation analysis was used to verify the role of candidate genes in pilus biosynthesis. Presented data support a model that CRP negatively regulates pilus biosynthesis through increased expression of flhDC and decreased expression of oxyR. Further studies are warranted to determine the mechanism by which these genes mediate pilus biosynthesis or function.
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Affiliation(s)
- Robert M Q Shanks
- The Charles T. Campbell Laboratory, UPMC Eye Center, Ophthalmology and Visual Sciences Research Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pa., USA.,The Charles T. Campbell Laboratory, UPMC Eye Center, Ophthalmology and Visual Sciences Research Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pa., USA
| | - Nicholas A Stella
- The Charles T. Campbell Laboratory, UPMC Eye Center, Ophthalmology and Visual Sciences Research Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pa., USA.,The Charles T. Campbell Laboratory, UPMC Eye Center, Ophthalmology and Visual Sciences Research Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pa., USA
| | - Kimberly M Brothers
- The Charles T. Campbell Laboratory, UPMC Eye Center, Ophthalmology and Visual Sciences Research Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pa., USA.,The Charles T. Campbell Laboratory, UPMC Eye Center, Ophthalmology and Visual Sciences Research Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pa., USA
| | - Denise M Polaski
- The Charles T. Campbell Laboratory, UPMC Eye Center, Ophthalmology and Visual Sciences Research Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pa., USA.,The Charles T. Campbell Laboratory, UPMC Eye Center, Ophthalmology and Visual Sciences Research Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pa., USA
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Wiedemann A, Virlogeux-Payant I, Chaussé AM, Schikora A, Velge P. Interactions of Salmonella with animals and plants. Front Microbiol 2015; 5:791. [PMID: 25653644 PMCID: PMC4301013 DOI: 10.3389/fmicb.2014.00791] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 12/22/2014] [Indexed: 12/16/2022] Open
Abstract
Salmonella enterica species are Gram-negative bacteria, which are responsible for a wide range of food- and water-borne diseases in both humans and animals, thereby posing a major threat to public health. Recently, there has been an increasing number of reports, linking Salmonella contaminated raw vegetables and fruits with food poisoning. Many studies have shown that an essential feature of the pathogenicity of Salmonella is its capacity to cross a number of barriers requiring invasion of a large variety of cells and that the extent of internalization may be influenced by numerous factors. However, it is poorly understood how Salmonella successfully infects hosts as diversified as animals or plants. The aim of this review is to describe the different stages required for Salmonella interaction with its hosts: (i) attachment to host surfaces; (ii) entry processes; (iii) multiplication; (iv) suppression of host defense mechanisms; and to point out similarities and differences between animal and plant infections.
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Affiliation(s)
- Agnès Wiedemann
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique Nouzilly, France ; UMR1282 Infectiologie et Santé Publique, Université François Rabelais Tours, France
| | - Isabelle Virlogeux-Payant
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique Nouzilly, France ; UMR1282 Infectiologie et Santé Publique, Université François Rabelais Tours, France
| | - Anne-Marie Chaussé
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique Nouzilly, France ; UMR1282 Infectiologie et Santé Publique, Université François Rabelais Tours, France
| | - Adam Schikora
- Institute for Phytopathology, Research Center for BioSystems, Land Use and Nutrition (IFZ), Justus Liebig University Giessen Giessen, Germany
| | - Philippe Velge
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique Nouzilly, France ; UMR1282 Infectiologie et Santé Publique, Université François Rabelais Tours, France
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Transcriptional Profiling of a Cross-Protective Salmonella enterica serovar Typhimurium UK-1 dam Mutant Identifies a Set of Genes More Transcriptionally Active Compared to Wild-Type, and Stably Transcribed across Biologically Relevant Microenvironments. Pathogens 2014; 3:417-436. [PMID: 25364573 PMCID: PMC4213855 DOI: 10.3390/pathogens3020417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Vaccination with Salmonella enterica serovar Typhimurium lacking DNA adenine methyltransferase confers cross-protective immunity against multiple Salmonella serotypes. The mechanistic basis is thought to be associated with the de-repression of genes that are tightly regulated when transiting from one microenvironment to another. This de-repression provides a potential means for the production of a more highly expressed and stable antigenic repertoire capable of inducing cross-protective immune responses. To identify genes encoding proteins that may contribute to cross-protective immunity, we used a Salmonella Typhimurium DNA adenine methyltransferase mutant strain (UK-1 dam mutant) derived from the parental UK-1 strain, and assessed the transcriptional profile of the UK-1 dam mutant and UK-1 strain grown under conditions that simulate the intestinal or endosomal microenvironments encountered during the infective process. As expected, the transcriptional profile of the UK-1 dam mutant identified a set of genes more transcriptionally active when compared directly to UK-1, and stably transcribed in biologically relevant culture conditions. Further, 22% of these genes were more highly transcribed in comparison to two other clinically-relevant Salmonella serovars. The strategy employed here helps to identify potentially conserved proteins produced by the UK-1 dam mutant that stimulate and/or modulate the development of cross-protective immune responses toward multiple Salmonella serotypes.
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Pathogenesis of human enterovirulent bacteria: lessons from cultured, fully differentiated human colon cancer cell lines. Microbiol Mol Biol Rev 2014; 77:380-439. [PMID: 24006470 DOI: 10.1128/mmbr.00064-12] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Hosts are protected from attack by potentially harmful enteric microorganisms, viruses, and parasites by the polarized fully differentiated epithelial cells that make up the epithelium, providing a physical and functional barrier. Enterovirulent bacteria interact with the epithelial polarized cells lining the intestinal barrier, and some invade the cells. A better understanding of the cross talk between enterovirulent bacteria and the polarized intestinal cells has resulted in the identification of essential enterovirulent bacterial structures and virulence gene products playing pivotal roles in pathogenesis. Cultured animal cell lines and cultured human nonintestinal, undifferentiated epithelial cells have been extensively used for understanding the mechanisms by which some human enterovirulent bacteria induce intestinal disorders. Human colon carcinoma cell lines which are able to express in culture the functional and structural characteristics of mature enterocytes and goblet cells have been established, mimicking structurally and functionally an intestinal epithelial barrier. Moreover, Caco-2-derived M-like cells have been established, mimicking the bacterial capture property of M cells of Peyer's patches. This review intends to analyze the cellular and molecular mechanisms of pathogenesis of human enterovirulent bacteria observed in infected cultured human colon carcinoma enterocyte-like HT-29 subpopulations, enterocyte-like Caco-2 and clone cells, the colonic T84 cell line, HT-29 mucus-secreting cell subpopulations, and Caco-2-derived M-like cells, including cell association, cell entry, intracellular lifestyle, structural lesions at the brush border, functional lesions in enterocytes and goblet cells, functional and structural lesions at the junctional domain, and host cellular defense responses.
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12
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Role of StdA in adhesion of Salmonella enterica serovar Enteritidis phage type 8 to host intestinal epithelial cells. Gut Pathog 2013; 5:43. [PMID: 24367906 PMCID: PMC3877977 DOI: 10.1186/1757-4749-5-43] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 12/21/2013] [Indexed: 12/31/2022] Open
Abstract
Background Salmonella is often implicated in foodborne outbreaks, and is a major public health concern in the United States and throughout the world. Salmonella enterica serovar Enteritidis (SE) infection in humans is often associated with the consumption of contaminated poultry products. Adhesion to epithelial cells in the intestinal mucosa is a major pathogenic mechanism of Salmonella in poultry. Transposon mutagenesis identified stdA as a potential adhesion mutant of SE. Therefore, we hypothesize StdA plays a significant role in adhesion of SE to the intestinal mucosa of poultry. Methods and results To test our hypothesis, we created a mutant of SE in which stdA was deleted. Growth and motility were assayed along with the in vitro and in vivo adhesion ability of the ∆stdA when compared to the wild-type SE strain. Our data showed a significant decrease in motility in ∆stdA when compared to the wild-type and complemented strain. A decrease in adhesion to intestinal epithelial cells as well as in the small intestine and cecum of poultry was observed in ∆stdA. Furthermore, the lack of adhesion correlated to a defect in invasion as shown by a cell culture model using intestinal epithelial cells and bacterial recovery from the livers and spleens of chickens. Conclusions These studies suggest StdA is a major contributor to the adhesion of Salmonella to the intestinal mucosa of poultry.
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Salmonella enterica serovar Typhimurium skills to succeed in the host: virulence and regulation. Clin Microbiol Rev 2013; 26:308-41. [PMID: 23554419 DOI: 10.1128/cmr.00066-12] [Citation(s) in RCA: 455] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is a primary enteric pathogen infecting both humans and animals. Infection begins with the ingestion of contaminated food or water so that salmonellae reach the intestinal epithelium and trigger gastrointestinal disease. In some patients the infection spreads upon invasion of the intestinal epithelium, internalization within phagocytes, and subsequent dissemination. In that case, antimicrobial therapy, based on fluoroquinolones and expanded-spectrum cephalosporins as the current drugs of choice, is indicated. To accomplish the pathogenic process, the Salmonella chromosome comprises several virulence mechanisms. The most important virulence genes are those located within the so-called Salmonella pathogenicity islands (SPIs). Thus far, five SPIs have been reported to have a major contribution to pathogenesis. Nonetheless, further virulence traits, such as the pSLT virulence plasmid, adhesins, flagella, and biofilm-related proteins, also contribute to success within the host. Several regulatory mechanisms which synchronize all these elements in order to guarantee bacterial survival have been described. These mechanisms govern the transitions from the different pathogenic stages and drive the pathogen to achieve maximal efficiency inside the host. This review focuses primarily on the virulence armamentarium of this pathogen and the extremely complicated regulatory network controlling its success.
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Sarnacki SH, Castañeda MDRA, Llana MN, Giacomodonato MN, Valvano MÁ, Cerquetti MC. Dam methylation participates in the regulation of PmrA/PmrB and RcsC/RcsD/RcsB two component regulatory systems in Salmonella enterica serovar Enteritidis. PLoS One 2013; 8:e56474. [PMID: 23418573 PMCID: PMC3572086 DOI: 10.1371/journal.pone.0056474] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 01/09/2013] [Indexed: 12/19/2022] Open
Abstract
The absence of Dam in Salmonella enterica serovar Enteritidis causes a defect in lipopolysaccharide (LPS) pattern associated to a reduced expression of wzz gene. Wzz is the chain length regulator of the LPS O-antigen. Here we investigated whether Dam regulates wzz gene expression through its two known regulators, PmrA and RcsB. Thus, the expression of rcsB and pmrA was monitored by quantitative real-time RT-PCR and Western blotting using fusions with 3×FLAG tag in wild type (wt) and dam strains of S. Enteritidis. Dam regulated the expression of both rcsB and pmrA genes; nevertheless, the defect in LPS pattern was only related to a diminished expression of RcsB. Interestingly, regulation of wzz in serovar Enteritidis differed from that reported earlier for serovar Typhimurium; RcsB induces wzz expression in both serovars, whereas PmrA induces wzz in S. Typhimurium but represses it in serovar Enteritidis. Moreover, we found that in S. Enteritidis there is an interaction between both wzz regulators: RcsB stimulates the expression of pmrA and PmrA represses the expression of rcsB. Our results would be an example of differential regulation of orthologous genes expression, providing differences in phenotypic traits between closely related bacterial serovars.
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Affiliation(s)
- Sebastián Hernán Sarnacki
- Instituto de Investigaciones en Microbiología y Parasitología Médica, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Ciencias y Técnicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
- * E-mail: (SHS); (MCC)
| | - María del Rosario Aya Castañeda
- Instituto de Investigaciones en Microbiología y Parasitología Médica, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Ciencias y Técnicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Mariángeles Noto Llana
- Instituto de Investigaciones en Microbiología y Parasitología Médica, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Ciencias y Técnicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Mónica Nancy Giacomodonato
- Instituto de Investigaciones en Microbiología y Parasitología Médica, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Ciencias y Técnicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
| | - Miguel Ángel Valvano
- Department of Microbiology and Immunology, Centre for Human Immunology, University of Western Ontario, London, Ontario, Canada
| | - María Cristina Cerquetti
- Instituto de Investigaciones en Microbiología y Parasitología Médica, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Ciencias y Técnicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina
- * E-mail: (SHS); (MCC)
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Expression of STM4467-encoded arginine deiminase controlled by the STM4463 regulator contributes to Salmonella enterica serovar Typhimurium virulence. Infect Immun 2012; 80:4291-7. [PMID: 23006851 DOI: 10.1128/iai.00880-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Arginine deiminase (ADI), carbamate kinase (CK), and ornithine transcarbamoylase (OTC) constitute the ADI system. In addition to metabolic functions, the ADI system has been implicated in the virulence of certain pathogens. The pathogenic intracellular bacterium Salmonella enterica serovar Typhimurium possesses the STM4467, STM4466, and STM4465 genes, which are predicted to encode ADI, CK, and OTC, respectively. Here we report that the STM4467 gene encodes an ADI and that ADI activity plays a role in the successful infection of a mammalian host by S. Typhimurium. An STM4467 deletion mutant was defective for replication inside murine macrophages and was attenuated for virulence in mice. We determined that a regulatory protein encoded by the STM4463 gene functions as an activator for STM4467 expression. The expression of the ADI pathway genes was enhanced inside macrophages in a process that required STM4463. Lack of STM4463 impaired the ability of S. Typhimurium to replicate within macrophages. A mutant defective in STM4467-encoded ADI displayed normal production of nitric oxide by macrophages.
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Kuo CJ, Bell H, Hsieh CL, Ptak CP, Chang YF. Novel mycobacteria antigen 85 complex binding motif on fibronectin. J Biol Chem 2011; 287:1892-902. [PMID: 22128161 DOI: 10.1074/jbc.m111.298687] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The members of the antigen 85 protein family (Ag85), consisting of members Ag85A, Ag85B, and Ag85C, are the predominantly secreted proteins of mycobacteria and possess the ability to specifically interact with fibronectin (Fn). Because Fn-binding proteins are likely to be important virulence factors of Mycobacterium spp., Ag85 may contribute to the adherence, invasion, and dissemination of organisms in host tissue. In this study, we reported the Fn binding affinity of Ag85A, Ag85B, and Ag85C from Mycobacterium avium subsp. paratuberculosis (MAP) (K(D) values were determined from 33.6 to 68.4 nm) and mapped the Ag85-binding motifs of Fn. Fn14, a type III module located on the heparin-binding domain II (Hep-2) of Fn, was discovered to interact with Ag85 from MAP. The peptide inhibition assay subsequently demonstrated that a peptide consisting of residues 17-26 from Fn14 ((17)SLLVSWQPPR(26), termed P17-26) could interfere with Ag85B binding to Fn (73.3% reduction). In addition, single alanine substitutions along the sequence of P17-26 revealed that the key residues involved in Ag85-Fn binding likely contribute through hydrophobic and charge interactions. Moreover, binding of Ag85 on Fn siRNA-transfected Caco2 cells was dramatically reduced (44.6%), implying the physiological significance of the Ag85-Fn interaction between mycobacteria and host cells during infection. Our results indicate that Ag85 binds to Fn at a novel motif and plays a critical role in mycobacteria adherence to host cells by initiating infection. Ag85 might serve as an important colonization factor potentially contributing to mycobacterial virulence.
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Affiliation(s)
- Chih-Jung Kuo
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
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17
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Juge N. Microbial adhesins to gastrointestinal mucus. Trends Microbiol 2011; 20:30-9. [PMID: 22088901 DOI: 10.1016/j.tim.2011.10.001] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 09/30/2011] [Accepted: 10/14/2011] [Indexed: 01/04/2023]
Abstract
The gastrointestinal tract (GIT) is lined by a layer of mucus formed by mucin glycoproteins. This layer constitutes a physical and chemical barrier between the intestinal contents and the underlying epithelia. In addition to this protective role, mucins harbor glycan-rich domains that provide preferential binding sites for pathogens and commensal bacteria. Although mucus-microbial interactions in the GIT play a crucial role in determining the outcome of relationships of both commensal and pathogens with the host, the adhesins and ligands involved in the interaction are poorly delineated. This review focuses on the current knowledge of microbial adhesins to gastrointestinal mucus and mucus components.
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Affiliation(s)
- Nathalie Juge
- Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, UK.
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More than one way to control hair growth: regulatory mechanisms in enterobacteria that affect fimbriae assembled by the chaperone/usher pathway. J Bacteriol 2011; 193:2081-8. [PMID: 21398554 DOI: 10.1128/jb.00071-11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Many gram-negative enterobacteria produce surface-associated fimbriae that facilitate attachment and adherence to eucaryotic cells and tissues. These organelles are believed to play an important role during infection by enabling bacteria to colonize specific niches within their hosts. One class of these fimbriae is assembled using a periplasmic chaperone and membrane-associated scaffolding protein that has been referred to as an usher because of its function in fimbrial biogenesis. The presence of multiple types of fimbriae assembled by the chaperone/usher pathway can be found both within a single bacterial species and also among different genera. One way of controlling fimbrial assembly in these bacteria is at the genetic level by positively or negatively regulating fimbrial gene expression. This minireview considers the mechanisms that have been described to control fimbrial gene expression and uses specific examples to demonstrate both unique and shared properties of such regulatory mechanisms.
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Lin YP, Kuo CJ, Koleci X, McDonough SP, Chang YF. Manganese binds to Clostridium difficile Fbp68 and is essential for fibronectin binding. J Biol Chem 2010; 286:3957-69. [PMID: 21062746 DOI: 10.1074/jbc.m110.184523] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile is an etiological agent of pseudomembranous colitis and antibiotic-associated diarrhea. Adhesion is the crucial first step in bacterial infection. Thus, in addition to toxins, the importance of colonization factors in C. difficile-associated disease is recognized. In this study, we identified Fbp68, one of the colonization factors that bind to fibronectin (Fn), as a manganese-binding protein (K(D) = 52.70 ± 1.97 nM). Furthermore, the conformation of Fbp68 changed dramatically upon manganese binding. Manganese binding can also stabilize the structure of Fbp68 as evidenced by the increased T(m) measured by thermodenatured circular dichroism and differential scanning calorimetry (CD, T(m) = 58-65 °C; differential scanning calorimetry, T(m) = 59-66 °C). In addition, enhanced tolerance to protease K also suggests greatly improved stability of Fbp68 through manganese binding. Fn binding activity was found to be dependent on manganese due to the lack of binding by manganese-free Fbp68 to Fn. The C-terminal 194 amino acid residues of Fbp68 (Fbp68C) were discovered to bind to the N-terminal domain of Fn (Fbp68C-NTD, K(D) = 233 ± 10 nM, obtained from isothermal titration calorimetry). Moreover, adhesion of C. difficile to Caco-2 cells can be partially blocked if cells are pretreated with Fbp68C, and the binding of Fbp68C on Fn siRNA-transfected cells was significantly reduced. These results raise the possibility that Fbp68 plays a key role in C. difficile adherence on host cells to initiate infection.
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Affiliation(s)
- Yi-Pin Lin
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
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Santos RL, Raffatellu M, Bevins CL, Adams LG, Tükel C, Tsolis RM, Bäumler AJ. Life in the inflamed intestine, Salmonella style. Trends Microbiol 2009; 17:498-506. [PMID: 19819699 DOI: 10.1016/j.tim.2009.08.008] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 08/28/2009] [Accepted: 08/28/2009] [Indexed: 12/12/2022]
Abstract
The lower gastrointestinal tract is densely populated with resident microbial communities (microbiota), which do not elicit overt host responses but rather provide benefit to the host, including niche protection from pathogens. However, introduction of bacteria into the underlying tissue evokes acute inflammation. Non-typhoidal Salmonella serotypes (NTS) elicit this stereotypic host response by actively penetrating the intestinal epithelium and surviving in tissue macrophages. Initial responses generated by bacterial host cell interaction are amplified in tissue through the interleukin (IL)-18/interferon-gamma and IL-23/IL-17 axes, resulting in the activation of mucosal barrier functions against NTS dissemination. However, the pathogen is adapted to survive antimicrobial defenses encountered in the lumen of the inflamed intestine. This strategy enables NTS to exploit inflammation to outcompete the intestinal microbiota, and promotes the Salmonella transmission by the fecal/oral route.
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Affiliation(s)
- Renato L Santos
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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Epigenetic regulation of the bacterial cell cycle. Curr Opin Microbiol 2009; 12:722-9. [PMID: 19783470 DOI: 10.1016/j.mib.2009.08.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Accepted: 08/16/2009] [Indexed: 01/15/2023]
Abstract
N(6)-methyl-adenines can serve as epigenetic signals for interactions between regulatory DNA sequences and regulatory proteins that control cellular functions, such as the initiation of chromosome replication or the expression of specific genes. Several of these genes encode master regulators of the bacterial cell cycle. DNA adenine methylation is mediated by Dam in gamma-proteobacteria and by CcrM in alpha-proteobacteria. A major difference between them is that CcrM is cell cycle regulated, while Dam is active throughout the cell cycle. In alpha-proteobacteria, GANTC sites can remain hemi-methylated for a significant period of the cell cycle, depending on their location on the chromosome. In gamma-proteobacteria, most GATC sites are only transiently hemi-methylated, except regulatory GATC sites that are protected from Dam methylation by specific DNA-binding proteins.
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The role of stj fimbrial operon in the intestinal persistence of Salmonella Typhimurium in mice. Biologia (Bratisl) 2009. [DOI: 10.2478/s11756-009-0170-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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23
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Dam methylation controls O-antigen chain length in Salmonella enterica serovar enteritidis by regulating the expression of Wzz protein. J Bacteriol 2009; 191:6694-700. [PMID: 19717610 DOI: 10.1128/jb.00839-09] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We reported previously that a Salmonella enterica serovar Enteritidis dam mutant expressing a truncated Dam protein does not agglutinate in the presence of specific antibodies against O9 polysaccharide. Here we investigate the participation of Dam in lipopolysaccharide (LPS) synthesis in Salmonella. The LPS O-antigen profiles of a dam null mutant (SEDeltadam) and the Salmonella serovar Enteritidis parental strain were examined by using electrophoresis and silver staining. Compared to the parental strain, SEDeltadam produced LPS with shorter O-antigen polysaccharide chains. Since Wzz is responsible for the chain length distribution of the O antigen, we investigated whether Dam methylation is involved in regulating wzz expression. Densitometry analysis showed that the amount of Wzz produced by SEDeltadam is threefold lower than the amount of Wzz produced by the parental strain. Concomitantly, the activity of the wzz promoter in SEDeltadam was reduced nearly 50% in logarithmic phase and 25% in stationary phase. These results were further confirmed by reverse transcription-PCR showing that wzz gene expression was threefold lower in the dam mutant than in the parental strain. Our results demonstrate that wzz gene expression is downregulated in a dam mutant, indicating that Dam methylation activates expression of this gene. This work indicates that wzz is a new target regulated by Dam methylation and demonstrates that DNA methylation not only affects the production of bacterial surface proteins but also the production of surface polysaccharides.
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Comparative analysis of attachment of Shiga-toxigenic Escherichia coli and Salmonella strains to cultured HT-29 and Caco-2 cell lines. Appl Environ Microbiol 2009; 75:1796-9. [PMID: 19168647 DOI: 10.1128/aem.02232-08] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability of Escherichia coli and Salmonella isolates to attach to Caco-2 and HT-29 cell monolayers was measured. All isolates displayed a greater ability to attach to Caco-2 cells than HT-29 cells, and overall E. coli isolates attached better to both cell lines than Salmonella isolates. Bacteria that were considered to be pathogenic displayed no greater ability to attach to cell lines than those that were not considered to be pathogenic. Additionally, no correlation was found between cell line attachment and previously determined hydrophobicity results.
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Marinus MG, Casadesus J. Roles of DNA adenine methylation in host-pathogen interactions: mismatch repair, transcriptional regulation, and more. FEMS Microbiol Rev 2009; 33:488-503. [PMID: 19175412 DOI: 10.1111/j.1574-6976.2008.00159.x] [Citation(s) in RCA: 200] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The DNA adenine methyltransferase (Dam methylase) of Gammaproteobacteria and the cell cycle-regulated methyltransferase (CcrM) methylase of Alphaproteobacteria catalyze an identical reaction (methylation of adenosine moieties using S-adenosyl-methionine as a methyl donor) at similar DNA targets (GATC and GANTC, respectively). Dam and CcrM are of independent evolutionary origin. Each may have evolved from an ancestral restriction-modification system that lost its restriction component, leaving an 'orphan' methylase devoted solely to epigenetic genome modification. The formation of 6-methyladenine reduces the thermodynamic stability of DNA and changes DNA curvature. As a consequence, the methylation state of specific adenosine moieties can affect DNA-protein interactions. Well-known examples include binding of the replication initiation complex to the methylated oriC, recognition of hemimethylated GATCs in newly replicated DNA by the MutHLS mismatch repair complex, and discrimination of methylation states in promoters and regulatory DNA motifs by RNA polymerase and transcription factors. In recent years, Dam and CcrM have been shown to play roles in host-pathogen interactions. These roles are diverse and have only partially been understood. Especially intriguing is the evidence that Dam methylation regulates virulence genes in Escherichia coli, Salmonella, and Yersinia at the posttranscriptional level.
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Affiliation(s)
- Martin G Marinus
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts, Worcester, USA
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26
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Clayton DJ, Bowen AJ, Hulme SD, Buckley AM, Deacon VL, Thomson NR, Barrow PA, Morgan E, Jones MA, Watson M, Stevens MP. Analysis of the role of 13 major fimbrial subunits in colonisation of the chicken intestines by Salmonella enterica serovar Enteritidis reveals a role for a novel locus. BMC Microbiol 2008; 8:228. [PMID: 19091138 PMCID: PMC2644700 DOI: 10.1186/1471-2180-8-228] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2008] [Accepted: 12/18/2008] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Salmonella enterica is a facultative intracellular pathogen of worldwide importance. Over 2,500 serovars exist and infections in humans and animals may produce a spectrum of symptoms from enteritis to typhoid depending on serovar- and host-specific factors. S. Enteritidis is the most prevalent non-typhoidal serovar isolated from humans with acute diarrhoeal illness in many countries. Human infections are frequently associated with direct or indirect contact with contaminated poultry meat or eggs owing to the ability of the organism to persist in the avian intestinal and reproductive tract. The molecular mechanisms underlying colonisation of poultry by S. Enteritidis are ill-defined. Targeted and genome-wide mutagenesis of S. Typhimurium has revealed conserved and host-specific roles for selected fimbriae in intestinal colonisation of different hosts. Here we report the first systematic analysis of each chromosomally-encoded major fimbrial subunit of S. Enteritidis in intestinal colonisation of chickens. RESULTS The repertoire, organisation and sequence of the fimbrial operons within members of S. enterica were compared. No single fimbrial locus could be correlated with the differential virulence and host range of serovars by comparison of available genome sequences. Fimbrial operons were highly conserved among serovars in respect of gene number, order and sequence, with the exception of safA. Thirteen predicted major fimbrial subunit genes were separately inactivated by lambda Red recombinase-mediated linear recombination followed by P22/int transduction. The magnitude and duration of intestinal colonisation by mutant and parent strains was measured after oral inoculation of out-bred chickens. Whilst the majority of S. Enteritidis major fimbrial subunit genes played no significant role in colonisation of the avian intestines, mutations affecting pegA in two different S. Enteritidis strains produced statistically significant attenuation. Plasmid-mediated trans-complementation partially restored the colonisation phenotype. CONCLUSION We describe the fimbrial gene repertoire of the predominant non-typhoidal S. enterica serovar affecting humans and the role played by each predicted major fimbrial subunit in intestinal colonisation of the primary reservoir. Our data support a role for PegA in the colonisation of poultry by S. Enteritidis and aid the design of improved vaccines.
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Affiliation(s)
- Debra J Clayton
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
| | - Alison J Bowen
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
| | - Scott D Hulme
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Anthony M Buckley
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
| | - Victoria L Deacon
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
| | - Nicholas R Thomson
- Pathogen Genomics, Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Paul A Barrow
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Eirwen Morgan
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
| | - Michael A Jones
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - Michael Watson
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
| | - Mark P Stevens
- Division of Microbiology, Institute for Animal Health, Compton, Berkshire, RG20 7NN, UK
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Chessa D, Winter MG, Jakomin M, Bäumler AJ. Salmonella enterica serotype Typhimurium Std fimbriae bind terminal alpha(1,2)fucose residues in the cecal mucosa. Mol Microbiol 2008; 71:864-75. [PMID: 19183274 DOI: 10.1111/j.1365-2958.2008.06566.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The std operon encodes a fimbrial adhesin of Salmonella enterica serotype Typhimurium that is required for attachment to intestinal epithelial cells and for cecal colonization in the mouse. To study the mechanism by which this virulence factor contributes to colonization we characterized its binding specificity. Std-mediated binding to human colonic epithelial (Caco-2) cells could be abrogated by removing N-linked glycans. Adherence of Std fimbriated S. Typhimurium to Caco-2 cells could be blocked by co-incubation with H type 2 oligosaccharide (Fucalpha1-2Galbeta1-4GlcNAc) or by pretreatment of cells with alpha1-2 fucosidase. In contrast, pretreatment of Caco-2 cells with neuraminidase or co-incubation with the type 2 disaccharide precursor (Galbeta1-4GlcNAc) did not reduce adherence of Std fimbriated S. Typhimurium. Binding of purified Std fimbriae to Fucalpha1-2Galbeta1-4GlcNAc in a solid phase binding assay was competitively inhibited by Ulex europaeus agglutinin-I (UEA-I), a lectin specific for Fucalpha1-2 moieties. Purified Std fimbriae and UEA both bound to a receptor localized in the mucus layer of the murine cecum. These data suggest that the std operon encodes an adhesin that binds an alpha1-2 fucosylated receptor(s) present in the cecal mucosa.
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Affiliation(s)
- Daniela Chessa
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Ave., Davis, CA 95616-8645, USA
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Regulation of the Salmonella enterica std fimbrial operon by DNA adenine methylation, SeqA, and HdfR. J Bacteriol 2008; 190:7406-13. [PMID: 18805972 DOI: 10.1128/jb.01136-08] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
DNA adenine methylase (dam) mutants of Salmonella enterica serovar Typhimurium grown under laboratory conditions express the std fimbrial operon, which is tightly repressed in the wild type. Here, we show that uncontrolled production of Std fimbriae in S. enterica serovar Typhimurium dam mutants contributes to attenuation in mice, as indicated by the observation that an stdA dam strain is more competitive than a dam strain upon oral infection. Dam methylation appears to regulate std transcription, rather than std mRNA stability or turnover. A genetic screen for std regulators showed that the GATC-binding protein SeqA directly or indirectly represses std expression, while the poorly characterized yifA gene product serves as an std activator. YifA encodes a putative LysR-like protein and has been renamed HdfR, like its Escherichia coli homolog. Activation of std expression by HdfR is observed only in dam and seqA backgrounds. These data suggest that HdfR directly or indirectly activates std transcription. Since SeqA is unable to bind nonmethylated DNA, it is possible that std operon derepression in dam and seqA mutants may result from unconstrained HdfR-mediated activation of std transcription. Derepression of std in dam and seqA mutants of S. enterica occurs in only a fraction of the bacterial population, suggesting the occurrence of either bistable expression or phase variation.
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