scholarly journals Enterotoxigenic Escherichia coli degrades the host MUC2 mucin barrier to facilitate critical pathogen-enterocyte interactions in human small intestine.

2021 ◽  
Author(s):  
Alaullah Sheikh ◽  
Tamding Wangdi ◽  
Tim J Vickers ◽  
Bailey Aaron ◽  
Margot Palmer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Small Intestine ◽  
Enterotoxigenic Escherichia Coli ◽  
Symptomatic Infection ◽  
Middle Income ◽  
Diarrheal Illness ◽  
Human Small Intestine ◽  
Heat Stable ◽  
Basic Sanitation ◽  
Epidemiology Studies

Enterotoxigenic Escherichia coli (ETEC) are a genetically diverse pathologic variant of E. coli defined by the production of heat-labile (LT) and/or heat-stable (ST) toxins. ETEC are estimated to cause hundreds of millions of cases of diarrheal illness annually. However, it is not clear that all strains are equally equipped to cause disease and asymptomatic colonization with ETEC is common in low-middle income regions lacking basic sanitation and clean water where ETEC are ubiquitous. Recent molecular epidemiology studies have revealed a significant association between strains which produce EatA, a secreted autotransporter protein, and the development of symptomatic infection. Here, we demonstrate that LT stimulates production of MUC2 mucin by goblet cells in human small intestine, enhancing the protective barrier between pathogens and enterocytes. In contrast, using explants of human small intestine as well as small intestinal enteroids, we show that EatA counters this host defense by engaging and degrading the MUC2 mucin barrier to promote bacterial access to target enterocytes and ultimately toxin delivery suggesting that EatA plays a crucial role in the molecular pathogenesis of ETEC. These findings may inform novel approaches to prevention of the acute diarrheal illness as well as the sequelae associated with ETEC and other pathogens that rely on EatA and similar proteases for efficient interaction with their human hosts.

scholarly journals Enterotoxigenic Escherichia coli degrades the host MUC2 mucin barrier to facilitate critical pathogen-enterocyte interactions in human small intestine.

2021 ◽  
Author(s):  
Alaullah Sheikh ◽  
Tamding Wangdi ◽  
Tim J Vickers ◽  
Bailey Aaron ◽  
Margot Perrin Palmer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Small Intestine ◽  
Enterotoxigenic Escherichia Coli ◽  
Symptomatic Infection ◽  
Middle Income ◽  
Diarrheal Illness ◽  
Human Small Intestine ◽  
Heat Stable ◽  
Basic Sanitation ◽  
Epidemiology Studies

Enterotoxigenic Escherichia coli (ETEC) are a genetically diverse pathologic variant of E. coli defined by the production of heat-labile (LT) and/or heat-stable (ST) toxins. ETEC are estimated to cause hundreds of millions of cases of diarrheal illness annually. However, it is not clear that all strains are equally equipped to cause disease and asymptomatic colonization with ETEC is common in low-middle income regions lacking basic sanitation and clean water where ETEC are ubiquitous. Recent molecular epidemiology studies have revealed a significant association between strains which produce EatA, a secreted autotransporter protein, and the development of symptomatic infection. Here, we demonstrate that LT stimulates production of MUC2 mucin by goblet cells in human small intestine, enhancing the protective barrier between pathogens and enterocytes. In contrast, using explants of human small intestine as well as small intestinal enteroids, we show that EatA counters this host defense by engaging and degrading the MUC2 mucin barrier to promote bacterial access to target enterocytes and ultimately toxin delivery suggesting that EatA plays a crucial role in the molecular pathogenesis of ETEC. These findings may inform novel approaches to prevention of the acute diarrheal illness as well as the sequelae associated with ETEC and other pathogens that rely on EatA and similar proteases for efficient interaction with their human hosts.

scholarly journals Confronting Challenges to Enterotoxigenic Escherichia coli Vaccine Development

2021 ◽  
Vol 2 ◽  
Author(s):  
James M. Fleckenstein
Keyword(s):  
Escherichia Coli ◽  
Vaccine Development ◽  
Enterotoxigenic Escherichia Coli ◽  
Symptomatic Infection ◽  
Middle Income ◽  
E Coli ◽  
Heat Stable ◽  
Structural Details ◽  
Basic Sanitation ◽  
Diarrheal Morbidity

The enterotoxigenic Escherichia coli (ETEC) are a diverse and genetically plastic pathologic variant (pathovar) of E. coli defined by their production of heat-labile (LT) and heat-stable (ST) enterotoxins. These pathogens, which came to recognition more than four decades ago in patients presenting with severe cholera-like diarrhea, are now known to cause hundreds of millions of cases of symptomatic infection annually. Children in low-middle income regions of the world lacking access to clean water and basic sanitation are disproportionately affected by ETEC. In addition to acute diarrheal morbidity, these pathogens remain a significant cause of mortality in children under the age of five years and have also been linked repeatedly to sequelae of childhood malnutrition and growth stunting. Vaccines that could prevent ETEC infections therefore remain a high priority. Despite several decades of effort, a licensed vaccine that protects against the breadth of these pathogens remains an aspirational goal, and the underlying genetic plasticity of E. coli has posed a fundamental challenge to development of a vaccine that can encompass the complete antigenic spectrum of ETEC. Nevertheless, novel strategies that include toxoids, a more complete understanding of ETEC molecular pathogenesis, structural details of target immunogens, and the discovery of more highly conserved antigens essential for virulence should accelerate progress and make a broadly protective vaccine feasible.

scholarly journals Immunizations with Enterotoxigenic Escherichia coli Heat-Stable Toxin Conjugates Engender Toxin-Neutralizing Antibodies in Mice That Also Cross-React with Guanylin and Uroguanylin

2019 ◽  
Vol 87 (7) ◽  
Author(s):  
Yuleima Diaz ◽  
Morten L. Govasli ◽  
Ephrem Debebe Zegeye ◽  
Halvor Sommerfelt ◽  
Hans Steinsland ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Cross Reactivity ◽  
Enterotoxigenic Escherichia Coli ◽  
Middle Income ◽  
Content Type ◽  
Endogenous Peptides ◽  
Heat Stable ◽  
Important Challenge

ABSTRACT Infection with enterotoxigenic Escherichia coli (ETEC) is a common cause of childhood diarrhea in low- and middle-income countries, as well as of diarrhea among travelers to these countries. In children, ETEC strains secreting the heat-stable toxin (ST) are the most pathogenic, and there are ongoing efforts to develop vaccines that target ST. One important challenge for ST vaccine development is to construct immunogens that do not elicit antibodies that cross-react with guanylin and uroguanylin, which are endogenous peptides involved in regulating the activity of the guanylate cyclase-C (GC-C) receptor. We immunized mice with both human ST (STh) and porcine ST (STp) chemically coupled to bovine serum albumin, and the resulting sera neutralized the toxic activities of both STh and STp. This suggests that a vaccine based on either ST variant can confer cross-protection. However, several anti-STh and anti-STp sera cross-reacted with the endogenous peptides, suggesting that the ST sequence must be altered to reduce the risk of unwanted cross-reactivity. Epitope mapping of four monoclonal anti-STh and six anti-STp antibodies, all of which neutralized both STh and STp, revealed that most epitopes appear to have at least one amino acid residue shared with guanylin or uroguanylin. Despite this, only one monoclonal antibody displayed demonstrable cross-reactivity to the endogenous peptides, suggesting that targeted mutations of a limited number of ST residues may be sufficient to obtain a safe ST-based vaccine.

scholarly journals Importance of Heat-Labile Enterotoxin in Colonization of the Adult Mouse Small Intestine by Human Enterotoxigenic Escherichia coli Strains

2006 ◽  
Vol 74 (2) ◽  
pp. 869-875 ◽  
Author(s):  
Kenneth P. Allen ◽  
Mildred M. Randolph ◽  
James M. Fleckenstein
Keyword(s):  
Escherichia Coli ◽  
Small Intestine ◽  
Diarrheal Disease ◽  
Vaccine Development ◽  
Small Animal ◽  
Enterotoxigenic Escherichia Coli ◽  
Colonization Factor ◽  
Heat Stable ◽  
Heat Labile ◽  
Colonization Factor Antigen I

ABSTRACT Enterotoxigenic Escherichia coli (ETEC) infections are a significant cause of diarrheal disease and infant mortality in developing countries. Studies of ETEC pathogenesis relevant to vaccine development have been greatly hampered by the lack of a suitable small-animal model of infection with human ETEC strains. Here, we demonstrate that adult immunocompetent outbred mice can be effectively colonized with the prototypical human ETEC H10407 strain (colonization factor antigen I; heat-labile and heat-stable enterotoxin positive) and that production of heat-labile holotoxin provides a significant advantage in colonization of the small intestine in this model.

scholarly journals Characterization of Immunological Cross-Reactivity between Enterotoxigenic Escherichia coli Heat-Stable Toxin and Human Guanylin and Uroguanylin

2014 ◽  
Vol 82 (7) ◽  
pp. 2913-2922 ◽  
Author(s):  
Arne M. Taxt ◽  
Yuleima Diaz ◽  
Amélie Bacle ◽  
Cédric Grauffel ◽  
Nathalie Reuter ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Diarrheal Disease ◽  
Cross Reactivity ◽  
Enterotoxigenic Escherichia Coli ◽  
Middle Income ◽  
Content Type ◽  
Cross Reactions ◽  
Endogenous Peptides ◽  
Heat Stable ◽  
Wide Range

ABSTRACTEnterotoxigenicEscherichia coli(ETEC) expressing the heat-stable toxin (ST) (human-type [STh] and porcine-type [STp] variants) is among the five most important enteric pathogens in young children living in low- and middle-income countries. ST mediates diarrheal disease through activation of the guanylate cyclase C (GC-C) receptor and is an attractive vaccine target with the potential to confer protection against a wide range of ETEC strains. However, immunological cross-reactivity to the endogenous GC-C ligands guanylin and uroguanylin is a major concern because of the similarities to ST in amino acid sequence, structure, and function. We have investigated the presence of similar epitopes on STh, STp, guanylin, and uroguanylin by analyzing these peptides in eight distinct competitive enzyme-linked immunosorbent assays (ELISAs). A fraction (27%) of a polyclonal anti-STh antibody and an anti-STh monoclonal antibody (MAb) cross-reacted with uroguanylin, the latter with a 73-fold-lower affinity. In contrast, none of the antibodies raised against STp, one polyclonal antibody and three MAbs, cross-reacted with the endogenous peptides. Antibodies raised against guanylin and uroguanylin showed partial cross-reactivity with the ST peptides. Our results demonstrate, for the first time, that immunological cross-reactions between ST and the endogenous peptides can occur. However, the partial nature and low affinity of the observed cross-reactions suggest that the risk of adverse effects from a future ST vaccine may be low. Furthermore, our results suggest that this risk may be reduced or eliminated by basing an ST immunogen on STp or a selectively mutated variant of STh.

scholarly journals NHERF3 is necessary for Escherichia coli heat-stable enterotoxin-induced inhibition of NHE3: differences in signaling in mouse small intestine and Caco-2 cells

2019 ◽  
Vol 317 (4) ◽  
pp. C737-C748
Author(s):  
Tiane Chen ◽  
Ruxian Lin ◽  
Leela Avula ◽  
Rafiquel Sarker ◽  
Jianbo Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Small Intestine ◽  
Intracellular Signaling ◽  
Cell Types ◽  
Enterotoxigenic Escherichia Coli ◽  
Intracellular Cgmp ◽  
Heat Stable ◽  
Mouse Small Intestine ◽  
Intracellular Ca ◽  
Multiple Cell

Enterotoxigenic Escherichia coli (ETEC) is a leading cause of childhood death from diarrhea and the leading cause of Traveler’s diarrhea. E. coli heat-stable enterotoxin (ST) is a major virulence factor of ETEC and inhibits the brush border Na/H exchanger NHE3 in producing diarrhea. NHE3 regulation involves multiprotein signaling complexes that form on its COOH terminus. In this study, the hypothesis was tested that ST signals via members of the Na/H exchanger regulatory factor (NHERF) family of scaffolding proteins, NHERF2, which had been previously shown to have a role, and now with concentration on a role for NHERF3. Two models were used: mouse small intestine and Caco-2/BBe cells. In both models, ST rapidly increased intracellular cGMP, inhibited NHE3 activity, and caused a quantitatively similar decrease in apical expression of NHE3. The transport effects were NHERF3 and NHERF2 dependent. Also, mutation of the COOH-terminal amino acids of NHERF3 supported that NHERF3-NHERF2 heterodimerization was likely to account for this dual dependence. The ST increase in cGMP in both models was partially dependent on NHERF3. The intracellular signaling pathways by which ST-cGMP inhibits NHE3 were different in mouse jejunum (activation of cGMP kinase II, cGKII) and Caco-2 cells, which do not express cGKII (elevation of intracellular Ca2+ concentration [Ca2+]i). The ST elevation of [Ca2+]i was from intracellular stores and was dependent on NHERF3-NHERF2. This study shows that intracellular signaling in the same diarrheal model in multiple cell types may be different; this has implications for therapeutic strategies, which often assume that models have similar signaling mechanisms.

Use of a Multiplex PCR System for the Simultaneous Detection of Heat Labile Toxin I and Heat Stable Toxin II Genes of Enterotoxigenic Escherichia coli in Skim Milk and Porcine Stool

1998 ◽  
Vol 61 (2) ◽  
pp. 141-145 ◽  
Author(s):  
HAU-YANG TSEN ◽  
LIANG-ZHAO JIAN ◽  
WAN-RONG CHI
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Simultaneous Detection ◽  
Skim Milk ◽  
Pcr Primers ◽  
Enterotoxigenic Escherichia Coli ◽  
Farm Animals ◽  
Target Cells ◽  
Heat Stable ◽  
Heat Labile

Enterotoxigenic Escherichia coli (ETEC) strains which produce heat labile and/or heat stable toxins (LT and ST) may cause diarrhea in humans and farm animals. Using PCR primers specific for the LT I and ST II genes, a multiplex PCR system which allows detection of LT I- and ST II-producing ETEC strains was developed. When skim milk was used for a PCR assay, it was found that if target cells in the sample were precultured in MacConkey broth for 8 h prior to PCR as few as 100 cells per ml of the sample could be detected. Without the preculture step, 104 CFU of target cells per 0.2 g of porcine stool specimen were required to generate visible PCR products. The multiplex PCR System can be used for rapid testing of fecal specimens, food and possibly environmental samples for the presence of ETEC strains.

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