Salmonella and Enteropathogenic Escherichia coli Interactions with Host Cells: Signaling Pathways

EcoSal Plus ◽  
2006 ◽  
Vol 2 (1) ◽  
Author(s):  
Danika L. Goosney ◽  
Sonya L. Kujat Choy ◽  
B. Brett Finlay
Keyword(s):  
Escherichia Coli ◽  
Signaling Pathways ◽  
Host Cells ◽  
Enteropathogenic Escherichia Coli

Interactions Between Salmonella Typhimurium, Enteropathogenic Escherichia Coli (EPEC), and Host Epithelial Cells

1995 ◽  
Vol 9 (1) ◽  
pp. 31-36 ◽  
Author(s):  
B.B. Finlay
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Salmonella Typhimurium ◽  
Host Cell ◽  
Inositol Phosphate ◽  
Enteric Pathogens ◽  
Host Protein ◽  
Host Cells ◽  
Enteropathogenic Escherichia Coli ◽  
Sequence Of Events

The interactions that occur between pathogenic micro-organisms and their host cells are complex and intimate. We have used two enteric pathogens, Salmonella typhimurium and enteropathogenic Escherichia coli (EPEC), to examine the interactions that occur between these organisms and epithelial cells. Although these are enteric pathogens, the knowledge and techniques developed from these systems may be applied to the study of dental pathogens. Both S. typhimurium and EPEC disrupt epithelial monolayer integrity, although by different mechanisms. Both pathogens cause loss of microvilli and re-arrangement of the underlying host cytoskeleton. Despite these similarities, both organisms send different signals into the host cell. EPEC signal transduction involves generation of intracellular calcium and inositol phosphate fluxes, and activation of host tyrosine kinases that results in tyrosine phosphorylation of a 90-kDa host protein. Bacterial mutants have been identifed that are deficient in signaling to the host. We propose a sequence of events that occur when EPEC interacts with epithelial cells. Once inside a host cell, S. typhimurium remains within a vacuole. To define some of the parameters of the intracellular environment, we constructed genetic fusions of known genes with lacZ, and used these fusions as reporter probes of the intracellular vacuolar environment. We have also begun to examine the bacterial and host cell factors necessary for S. typhimurium to multiply within epithelial cells. We found that this organism triggers the formation of novel tubular lysosomes, and these structures are linked with intracellular replication.

EscI: a crucial component of the type III secretion system forms the inner rod structure in enteropathogenic Escherichia coli

2012 ◽  
Vol 442 (1) ◽  
pp. 119-125 ◽  
Author(s):  
Neta Sal-Man ◽  
Wanyin Deng ◽  
B. Brett Finlay
Keyword(s):  
Escherichia Coli ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Integral Membrane Protein ◽  
Secretion System ◽  
Host Cells ◽  
Enteropathogenic Escherichia Coli ◽  
Bacterial Membranes ◽  
Type Iii ◽  
Protein Functions

The T3SS (type III secretion system) is a multi-protein complex that plays a central role in the virulence of many Gram-negative bacterial pathogens. This apparatus spans both bacterial membranes and transports virulence factors from the bacterial cytoplasm into eukaryotic host cells. The T3SS exports substrates in a hierarchical and temporal manner. The first secreted substrates are the rod/needle proteins which are incorporated into the T3SS apparatus and are required for the secretion of later substrates, the translocators and effectors. In the present study, we provide evidence that rOrf8/EscI, a poorly characterized locus of enterocyte effacement-encoded protein, functions as the inner rod protein of the T3SS of EPEC (enteropathogenic Escherichia coli). We demonstrate that EscI is essential for type III secretion and is also secreted as an early substrate of the T3SS. We found that EscI interacts with EscU, the integral membrane protein that is linked to substrate specificity switching, implicating EscI in the substrate-switching event. Furthermore, we showed that EscI self-associates and interacts with the outer membrane secretin EscC, further supporting its function as an inner rod protein. Overall, the results of the present study suggest that EscI is the YscI/PrgJ/MxiI homologue in the T3SS of attaching and effacing pathogens.

scholarly journals Expression of the Virulence Factor, BfpA, by Enteropathogenic Escherichia coli is Essential for Apoptosis Signalling but not for NF-kappaB Activation in Host Cells

2005 ◽  
Vol 61 (6) ◽  
pp. 511-519 ◽  
Author(s):  
A. R. Melo ◽  
E. B. Lasunskaia ◽  
C. M. C. de Almeida ◽  
A. Schriefer ◽  
T. L. Kipnis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factor ◽  
Host Cells ◽  
Enteropathogenic Escherichia Coli ◽  
Nf Kappab

Adhesion of enteropathogenic Escherichia coli to host cells

2003 ◽  
Vol 5 (6) ◽  
pp. 359-372 ◽  
Author(s):  
Jean-Philippe Nougayrede ◽  
Paula J. Fernandes ◽  
Michael S. Donnenberg
Keyword(s):  
Escherichia Coli ◽  
Host Cells ◽  
Enteropathogenic Escherichia Coli

scholarly journals Agents That Inhibit Rho, Rac, and Cdc42 Do Not Block Formation of Actin Pedestals in HeLa Cells Infected with Enteropathogenic Escherichia coli

1998 ◽  
Vol 66 (4) ◽  
pp. 1755-1758 ◽  
Author(s):  
Goni Ben-Ami ◽  
Vered Ozeri ◽  
Emanuel Hanski ◽  
Fred Hofmann ◽  
Klaus Aktories ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Clostridium Difficile ◽  
Hela Cells ◽  
Dominant Negative ◽  
Host Cells ◽  
Infected Host ◽  
Enteropathogenic Escherichia Coli ◽  
Toxin B ◽  
Block Formation

ABSTRACT Enteropathogenic Escherichia coli (EPEC) induces formation of actin pedestals in infected host cells. Agents that inhibit the activity of Rho, Rac, and Cdc42, includingClostridium difficile toxin B (ToxB), compactin, and dominant negative Rho, Rac, and Cdc42, did not inhibit formation of actin pedestals. In contrast, treatment of HeLa cells with ToxB inhibited EPEC invasion. Thus, Rho, Rac, and Cdc42 are not required for assembly of actin pedestals; however, they may be involved in EPEC uptake by HeLa cells.

Two pathways for ATP release from host cells in enteropathogenicEscherichia coliinfection

2005 ◽  
Vol 289 (3) ◽  
pp. G407-G417 ◽  
Author(s):  
John K. Crane ◽  
Tonniele M. Naeher ◽  
Shilpa S. Choudhari ◽  
Elisa M. Giroux
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Host Cell ◽  
Atp Release ◽  
Host Cells ◽  
Specific Cell ◽  
Hypotonic Medium ◽  
Enteropathogenic Escherichia Coli ◽  
Extracellular Adenosine ◽  
Transfected Cells

We previously reported that enteropathogenic Escherichia coli (EPEC) infection triggered a large release of ATP from the host cell that was correlated with and dependent on EPEC-induced killing of the host cell. We noted, however, that under some circumstances, EPEC-induced ATP release exceeded that which could be accounted for on the basis of host cell killing. For example, EPEC-induced ATP release was potentiated by noncytotoxic agents that elevate host cell cAMP, such as forskolin and cholera toxin, and by exposure to hypotonic medium. These findings and the performance of the EPEC espF mutant led us to hypothesize that the CFTR plays a role in EPEC-induced ATP release that is independent of cell death. We report the results of experiments using specific, cell-permeable CFTR activators and inhibitors, as well as transfection of the CFTR into non-CFTR-expressing cell lines, which incriminate the CFTR as a second pathway for ATP release from host cells. Increased ATP release via CFTR is not accompanied by an increase in EPEC adherence to transfected cells. The CFTR-dependent ATP release pathway becomes activated endogenously later in EPEC infection, and this activation is mediated, at least in part, by generation of extracellular adenosine from the breakdown of released ATP.

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