title: Transcriptional modulation of enterotoxigenic Escherichia coli virulence genes in response to epithelial cell interactions.
abstract: Enterotoxigenic Escherichia coli (ETEC) strains are a leading cause of morbidity and mortality due to diarrheal illness in developing countries. There is currently no effective vaccine against these important pathogens. Because genes modulated by pathogen-host interactions potentially encode putative vaccine targets, we investigated changes in gene expression and surface morphology of ETEC upon interaction with intestinal epithelial cells in vitro. Pan-genome microarrays, quantitative reverse transcriptase PCR (qRT-PCR), and transcriptional reporter fusions of selected promoters were used to study changes in ETEC transcriptomes. Flow cytometry, immunofluorescence microscopy, and scanning electron microscopy were used to investigate alterations in surface antigen expression and morphology following pathogen-host interactions. Following host cell contact, genes for motility, adhesion, toxin production, immunodominant peptides, and key regulatory molecules, including cyclic AMP (cAMP) receptor protein (CRP) and c-di-GMP, were substantially modulated. These changes were accompanied by visible changes in both ETEC architecture and the expression of surface antigens, including a novel highly conserved adhesin molecule, EaeH. The studies reported here suggest that pathogen-host interactions are finely orchestrated by ETEC and are characterized by coordinated responses involving the sequential deployment of multiple virulence molecules. Elucidation of the molecular details of these interactions could highlight novel strategies for development of vaccines for these important pathogens.
authors.affiliation: Research Service, Veterans Affairs Medical Center, Memphis, Tennessee, USA.
authors.forename: Rita
authors.initials: R
authors.lastname: Kansal
authors.forename: David A
authors.initials: DA
authors.lastname: Rasko
authors.forename: Jason W
authors.initials: JW
authors.lastname: Sahl
authors.forename: George P
authors.initials: GP
authors.lastname: Munson
authors.forename: Koushik
authors.initials: K
authors.lastname: Roy
authors.forename: Qingwei
authors.initials: Q
authors.lastname: Luo
authors.forename: Alaullah
authors.initials: A
authors.lastname: Sheikh
authors.forename: Kurt J
authors.initials: KJ
authors.lastname: Kuhne
authors.forename: James M
authors.initials: JM
authors.lastname: Fleckenstein
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D054307:Enterotoxigenic Escherichia coli / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity*; D004847:Epithelial Cells / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D004927:Escherichia coli Infections / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics / Q000276:immunology; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000276:immunology; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000276:immunology / Q000382:microbiology; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000276:immunology; D011953:Receptors, Cyclic AMP / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics / Q000276:immunology; D059467:Transcriptome / Q000235:genetics / Q000276:immunology; D014774:Virulence
chemical_list: D018829:Adhesins, Bacterial; D000954:Antigens, Surface; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D011953:Receptors, Cyclic AMP; C047947:cyclic AMP receptor protein, E coli; C062025:bis(3',5')-cyclic diguanylic acid; D006152:Cyclic GMP