Signal transduction in human epithelial cells infected with attaching and effacing Escherichia coli in vitro

Dytoc, Marlene; Fedorko, Ludwik; Sherman, Philip M.

doi:10.1016/0016-5085(94)90004-3

Cited by 76 publications

(72 citation statements)

References 30 publications

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“…This suggests that Bfp are not essential for full EPEC adherence to intestinal cells and therefore that a second adhesin may be responsible for initial interactions with the host cell. A similar conclusion was reached previously with the characterization of the AF/R1 adhesin of the rabbit EPEC strain RDEC-1 (190), and the concept is supported by recent evidence from a study of EHEC (44), which showed that serotype O157:H7 possesses an eae homologue but serotype O113:H21 does not, suggesting that the latter uses a different adherence mechanism. A second adhesin has been found in AE strains of E. coli that are pathogenic for rabbits, particularly strains of serotype O103:K Ϫ :H2 (135).…”

Section: Bundle-forming Pilisupporting

confidence: 86%

Virulence of EnteropathogenicEscherichia coli, a Global Pathogen

et al. 2003

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Enteropathogenic Escherichia coli (EPEC) remains an important cause of diarrheal disease worldwide. Research into EPEC is intense and provides a good virulence model of other E. coli infections as well as other pathogenic bacteria. Although the virulence mechanisms are now better understood, they are extremely complex and much remains to be learnt. The pathogenesis of EPEC depends on the formation of an ultrastructural lesion in which the bacteria make intimate contact with the host apical enterocyte membrane. The formation of this lesion is a consequence of the ability of EPEC to adhere in a localized manner to the host cell, aided by bundle-forming pili. Tyrosine phosphorylation and signal transduction events occur within the host cell at the lesion site, leading to a disruption of the host cell mechanisms and, consequently, to diarrhea. These result from the action of highly regulated EPEC secreted proteins which are released via a type III secretion system, many genes of which are located within a pathogenicity island known as the locus of enterocyte effacement. Over the last few years, dramatic increases in our knowledge of EPEC virulence have taken place. This review therefore aims to provide a broad overview of and update to the virulence aspects of EPEC

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Section: Bundle-forming Pilisupporting

confidence: 86%

Virulence of EnteropathogenicEscherichia coli, a Global Pathogen

et al. 2003

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“…Early studies on signal transduction events induced by EPEC showed an increase in intracellular calcium ([Ca 2 ] int ) in infected cells, which was dependent upon a functional type III secretion system and intimate attachment (Baldwin et al, 1991;Dytoc et al, 1994). In addition, sequestering the [Ca 2 ] int by BAPTA treatment inhibited pedestal formation, arguing for a role of calcium release in EPEC-induced actin rearrangements (Baldwin et al, 1991).…”

Section: The Calcium Questionmentioning

confidence: 99%

Enteropathogenic Escherichia coli (EPEC) attachment to epithelial cells: exploiting the host cell cytoskeleton from the outside

2000

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SummaryEnteropathogenic Escherichia coli (EPEC), a leading cause of human infantile diarrhoea, is the prototype for a family of intestinal bacterial pathogens that induce attaching and effacing (A/E) lesions on host cells. A/E lesions are characterized by localized effacement of the brush border of enterocytes, intimate bacterial attachment and pedestal formation beneath the adherent bacteria. As a result of some recent breakthrough discoveries, EPEC has now emerged as a fascinating paradigm for the study of host±pathogen interactions and cytoskeletal rearrangements that occur at the host cell membrane. EPEC uses a type III secretion machinery to attach to epithelial cells, translocating its own receptor for intimate attachment, Tir, into the host cell, which then binds to intimin on the bacterial surface. Studies of EPECinduced cytoskeletal rearrangements have begun to provide clues as to the mechanisms used by this pathogen to subvert the host cell cytoskeleton and signalling pathways. These ®ndings have unravelled new ways by which pathogenic bacteria exploit host processes from the cell surface and have shed new light on how EPEC might cause diarrhoea. EPEC, a model extracellular pathogenAmong the many themes in bacterial pathogenesis, determining how bacteria interact with host cells, including subversion of the cellular cytoskeleton and signal transduction pathways, remains of major interest. Most of the pathogens for which these aspects have been extensively studied, such as Salmonella, Shigella and Listeria species, illustrate that pathogens have evolved strategies to hijack the host cell machinery for invasive purposes. They use the intestinal barrier as an entry site, exploiting the target host cell cytoskeletal machinery to trigger their uptake by non-phagocytic cells, thereby gaining access to the host. Enteropathogenic Escherichia coli (EPEC), a major cause of diarrhoea in the developing world, colonizes the intestinal epithelial surface and exerts its pathologic effects by intimately attaching to the surface of enterocytes, causing histopathological alterations called the attaching/effacing (A/E) lesion. A/E lesions result from degeneration of the enterocyte brush border through the reorganization of the underlying cytoskeleton. This is triggered by bacteria attached to the surface and leads to the localized loss of microvilli and the formation of actin-rich pedestals upon which EPEC reside (Frankel et al., 1998a). Several other pathogens, such as enterohaemorrhagic E. coli (EHEC), which is associated with haemolytic±uraemic syndrome, Citrobacter rodentium and Hafnia alvei, also induce A/E lesion formation upon infection, but EPEC has been the most well studied of these pathogens and thus serves as the paradigm.Like several Gram-negative animal and plant pathogens, EPEC possesses a type III secretion machinery, which is designed to secrete key virulence factors and directly inject some of them into the host cell cytosol by functioning as a`molecular syringe ' (Hueck, 1998). Recently, some new and s...

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“…The involvement of these proteins in EPEC pathogenesis has not been explored. Several host signal transduction pathways are activated following EPEC attachment (4,15), and host intestinal epithelial functions, including ion transport (12,23), immune response, (49) and tight junction (TJ) barrier function (10,44,53,61), are perturbed. The host cell proteins involved in mediating the cross talk between adherent bacteria and/or bacterial proteins are not known.…”

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confidence: 99%

Enteropathogenic Escherichia coli Activates Ezrin, Which Participates in Disruption of Tight Junction Barrier Function

et al. 2001

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Enteropathogenic Escherichia coli (EPEC) is an important human intestinal pathogen, especially in infants. EPEC adherence to intestinal epithelial cells induces the accumulation of a number of cytoskeletal proteins beneath the bacteria, including the membrane-cytoskeleton linker ezrin. Evidence suggests that ezrin can participate in signal transduction. The aim of this study was to determine whether ezrin is activated following EPEC infection and if it is involved in the cross talk with host intestinal epithelial cells. We show here that following EPEC attachment to intestinal epithelial cells there was significant phosphorylation of ezrin, first on threonine and later on tyrosine residues. A significant increase in cytoskeleton-associated ezrin occurred following phosphorylation, suggesting activation of this molecule. Nonpathogenic E. coli and EPEC strains harboring mutations in type III secretion failed to elicit this response. Expression of dominant-negative ezrin significantly decreased the EPEC-elicited association of ezrin with the cytoskeleton and attenuated the disruption of intestinal epithelial tight junctions. These results suggest that ezrin is involved in transducing EPEC-initiated signals that ultimately affect host physiological functions.

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Signal transduction in human epithelial cells infected with attaching and effacing Escherichia coli in vitro

Cited by 76 publications

References 30 publications

Virulence of EnteropathogenicEscherichia coli, a Global Pathogen

Virulence of EnteropathogenicEscherichia coli, a Global Pathogen

Enteropathogenic Escherichia coli (EPEC) attachment to epithelial cells: exploiting the host cell cytoskeleton from the outside

Enteropathogenic Escherichia coli Activates Ezrin, Which Participates in Disruption of Tight Junction Barrier Function

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