scholarly journals Shiga Toxin 1 Triggers a Ribotoxic Stress Response Leading to p38 and JNK Activation and Induction of Apoptosis in Intestinal Epithelial Cells

2003 ◽  
Vol 71 (3) ◽  
pp. 1497-1504 ◽  
Author(s):  
Wendy E. Smith ◽  
Anne V. Kane ◽  
Sausan T. Campbell ◽  
David W. K. Acheson ◽  
Brent H. Cochran ◽  
...  
Keyword(s):  
Shiga Toxin ◽  
Intestinal Epithelial Cell ◽  
Caspase 3 ◽  
Intestinal Epithelial Cells ◽  
Epithelial Cell Line ◽  
Intestinal Epithelial ◽  
Shiga Toxins ◽  
Ribotoxic Stress Response ◽  
A Subunit ◽  
Jnk Activation

ABSTRACT Shiga toxins made by Shiga toxin-producing Escherichia coli (STEC) are associated with hemolytic uremic syndrome. Shiga toxins (Stxs) may access the host systemic circulation by absorption across the intestinal epithelium. The effects of Stxs on this cell layer are not completely understood, although animal models of STEC infection suggest that, in the gut, Stxs may participate in both immune activation and apoptosis. Stxs have one enzymatically active A subunit associated with five identical B subunits. The A subunit inactivates ribosomes by cleaving a specific adenine from the 28S rRNA. We have previously shown that Stxs can induce multiple C-X-C chemokines in intestinal epithelial cells in vitro, including interleukin-8 (IL-8), and that Stx-induced IL-8 expression is linked to induction of c-Jun mRNA and p38 mitogen-activated protein (MAP) kinase pathway activity. We now report Stx1 induction of both primary response genes c-jun and c-fos and activation of the stress-activated protein kinases, JNK/SAPK and p38, in the intestinal epithelial cell line HCT-8. By 1 h of exposure to Stx1, mRNAs for c-jun and c-fos are induced, and both JNK and p38 are activated; activation of both kinases persisted up to 24 h. Stx1 enzymatic activity was required for kinase activation; a catalytically defective mutant toxin did not activate either. Stx1 treatment of HCT-8 cells resulted in cell death that was associated with caspase 3 cleavage and internucleosomal DNA fragmentation; this cytotoxicity also required Stx1 enzymatic activity. Blocking Stx1-induced p38 and JNK activation with the inhibitor SB202190 prevented cell death and diminished Stx1-associated caspase 3 cleavage. In summary, these data link the Stx1-induced ribotoxic stress response with both chemokine expression and apoptosis in the intestinal epithelial cell line HCT-8 and suggest that blocking host cell MAP kinases may prevent these Stx-associated events.

scholarly journals Shiga Toxin 2e-Producing Escherichia coli Isolates from Humans and Pigs Differ in Their Virulence Profiles and Interactions with Intestinal Epithelial Cells

2005 ◽  
Vol 71 (12) ◽  
pp. 8855-8863 ◽  
Author(s):  
Anne-Katharina Sonntag ◽  
Martina Bielaszewska ◽  
Alexander Mellmann ◽  
Nadine Dierksen ◽  
Peter Schierack ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Shiga Toxin ◽  
Intestinal Epithelial Cell ◽  
Intestinal Epithelial Cells ◽  
Epithelial Cell Line ◽  
Uptake System ◽  
Intestinal Epithelial ◽  
E Coli

ABSTRACT Thirteen Escherichia coli strains harboring stx 2e were isolated from 11,056 human stools. This frequency corresponded to the presence of the stx 2e allele in 1.7% of all Shiga toxin-producing E. coli (STEC) strains. The strains harboring stx 2e were associated with mild diarrhea (n = 9) or asymptomatic infections (n= 4). Because STEC isolates possessing stx 2e are porcine pathogens, we compared the human STEC isolates with stx 2e-harboring E. coli isolated from piglets with edema disease and postweaning diarrhea. All pig isolates possessed the gene encoding the F18 adhesin, and the majority possessed adhesin involved in diffuse adherence; these adhesins were absent from all the human STEC isolates. In contrast, the high-pathogenicity island encoding an iron uptake system was found only in human isolates. Host-specific patterns of interaction with intestinal epithelial cells were observed. All human isolates adhered to human intestinal epithelial cell lines T84 and HCT-8 but not to pig intestinal epithelial cell line IPEC-J2. In contrast, the pig isolates completely lysed human epithelial cells but not IPEC-J2 cells, to which most of them adhered. Our data demonstrate that E. coli isolates producing Shiga toxin 2e have imported specific virulence and fitness determinants which allow them to adapt to the specific hosts in which they cause various forms of disease.

ADAM-15 inhibits wound healing in human intestinal epithelial cell monolayers

2005 ◽  
Vol 288 (2) ◽  
pp. G346-G353 ◽  
Author(s):  
Laetitia Charrier ◽  
Yutao Yan ◽  
Adel Driss ◽  
Christian L. Laboisse ◽  
Shanthi V. Sitaraman ◽  
...  
Keyword(s):  
Wound Healing ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cell ◽  
Intestinal Epithelial Cells ◽  
Epithelial Cell Line ◽  
Intestinal Epithelial ◽  
Coding Region ◽  
Human Intestinal Epithelial Cell ◽  
New Variant

The disintegrin metalloproteases (or ADAMs) are membrane-anchored glycoproteins that have been implicated in cell-cell or cell-matrix interactions and in proteolysis of molecules on the cell surface. The expression and/or the pathophysiological implications of ADAMs are not known in intestinal epithelial cells. Therefore, our aim was to investigate the expression and the role of ADAMs in intestinal epithelial cells. Expression of ADAMs was assessed by RT-PCR, Western blot analysis, and immunufluorescence experiments. Wound-healing experiments were performed by using the electric cell substrate impedence sensing technology. Our results showed that ADAMs-10, -12, and -15 mRNA are expressed in the colonic human cell lines Caco2-BBE and HT29-Cl.19A. An ADAM-15 complementary DNA cloned from Caco2-BBE poly(A)+ RNA, and encompassing the entire coding region, was found to be shorter and to present a different region encoding the cytoplasmic tail compared with ADAM-15 sequence deposited in the database. In Caco2-BBE cells and colonic epithelial cells, ADAM-15 protein was found in the apical, basolateral, and intracellular compartments. We also showed that the overexpression of ADAM-15 reduced cell migration in a wound-healing assay in Caco2-BBE monolayers. Our data show that 1) ADAM-15 is expressed in human intestinal epithelia, 2) a new variant of ADAM-15 is expressed in a human intestinal epithelial cell line, and 3) ADAM-15 is involved in intestinal epithelial cells wound-healing processes. Together, these results suggest that ADAM-15 may have important pathophysiological roles in intestinal cells.

scholarly journals Macropinocytosis in Shiga toxin 1 uptake by human intestinal epithelial cells and transcellular transcytosis

2009 ◽  
Vol 296 (1) ◽  
pp. G78-G92 ◽  
Author(s):  
Irina Malyukova ◽  
Karen F. Murray ◽  
Chengru Zhu ◽  
Edgar Boedeker ◽  
Anne Kane ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Shiga Toxin ◽  
Intestinal Epithelial Cells ◽  
Enterohemorrhagic Escherichia Coli ◽  
Apical Surface ◽  
Intestinal Epithelial ◽  
Shiga Toxins ◽  
E Coli ◽  
Human Intestinal Epithelial Cells ◽  
Toxin Uptake

Shiga toxin 1 and 2 production is a cardinal virulence trait of enterohemorrhagic Escherichia coli infection that causes a spectrum of intestinal and systemic pathology. However, intestinal sites of enterohemorrhagic E. coli colonization during the human infection and how the Shiga toxins are taken up and cross the globotriaosylceramide (Gb3) receptor-negative intestinal epithelial cells remain largely uncharacterized. We used samples of human intestinal tissue from patients with E. coli O157:H7 infection to detect the intestinal sites of bacterial colonization and characterize the distribution of Shiga toxins. We further used a model of largely Gb3-negative T84 intestinal epithelial monolayers treated with B-subunit of Shiga toxin 1 to determine the mechanisms of non-receptor-mediated toxin uptake. We now report that E. coli O157:H7 were found at the apical surface of epithelial cells only in the ileocecal valve area and that both toxins were present in large amounts inside surface and crypt epithelial cells in all tested intestinal samples. Our in vitro data suggest that macropinocytosis mediated through Src activation significantly increases toxin endocytosis by intestinal epithelial cells and also stimulates toxin transcellular transcytosis. We conclude that Shiga toxin is taken up by human intestinal epithelial cells during E. coli O157:H7 infection regardless of the presence of bacterial colonies. Macropinocytosis might be responsible for toxin uptake by Gb3-free intestinal epithelial cells and transcytosis. These observations provide new insights into the understanding of Shiga toxin contribution to enterohemorrhagic E. coli-related intestinal and systemic diseases.

Glutamine protects intestinal epithelial cells: role of inducible HSP70

1997 ◽  
Vol 272 (4) ◽  
pp. G879-G884 ◽  
Author(s):  
P. E. Wischmeyer ◽  
M. W. Musch ◽  
M. B. Madonna ◽  
R. Thisted ◽  
E. B. Chang
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Mucosal Healing ◽  
Epithelial Cell Line ◽  
Protective Effects ◽  
Intestinal Epithelial ◽  
Cellular Protection ◽  
Gut Mucosa ◽  
Shock Proteins ◽  
Hsp70 Induction

Glutamine (Gln) protects gut mucosa against injury and promotes mucosal healing. Because the induction of heat shock proteins (HSP) protects cells under conditions of stress, we determined whether Gln conferred protection against stress in an intestinal epithelial cell line through HSP induction. Gln added to IEC-18 cells induces an increase in HSP70, a concentration-dependent effect also seen with mRNA. Two forms of injury, lethal heat (49 degrees C) and oxidant, were used, and viability was determined by 51Cr release. Gln-treated cells were significantly more resistant to injury. Treatment with 6-diazo-5-oxo-L-norleucine (DON), a nonmetabolizable analog of Gln, induced HSP70 and protected cells from injury, but less than Gln. These findings suggest that the effects of Gln on HSP70 induction and cellular protection are mediated by metabolic and nonmetabolic mechanisms. To determine whether HSP induction was central to the action of Gln and DON, quercetin, which blocks HSP induction, was used. Quercetin blocked HSP70 induction and the protective effect of Gln and DON. We conclude that the protective effects of Gln in intestinal epithelial cells are in part mediated by HSP70 induction.

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