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Shiga toxin mode of action in E. coli O157:H7 disease
1Department of Microbiology and Immunology, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA. Tom_Obrig@urmc.rochester.edu
Abstract:
Shiga toxins (Stx) are virulence factors produced by selected bacteria pathogenic for humans. These multicomponent protein complexes are among the more potent toxins known. As inhibitors of eukaryotic protein synthesis, these toxins selectively inactivate ribosomes in an enzymatic manner. Specificity of cell targeting is determined by the high-affinity binding of Stx to its receptor, a glycosphingolipid (Gb3) located in the plasma membrane or some eukaryotic cells. Elaborated by food-borne E. coli O157:H7 bacteria, isotypes of Stx (Stx1 & Stx2) are required for the ensuing vascular changes in humans, including hemorrhagic colitis and renal hemolytic uremic syndrome. Experimental therapeutic intervention of Stx-associated disease includes the Stx receptor immobilized on biologically inert particles designed for oral presentation.
Insights
Shiga toxins (Stx) are potent bacterial toxins that inhibit protein synthesis by targeting ribosomes. Immobilizing the Stx receptor (Gb3) on particles offers a novel therapeutic strategy against Stx-associated diseases.
Area of Science:
- Microbiology
- Toxicology
- Molecular Biology
Background:
- Shiga toxins (Stx) are potent virulence factors produced by pathogenic bacteria like E. coli O157:H7.
- These toxins inhibit eukaryotic protein synthesis by enzymatically inactivating ribosomes.
- Stx binding specificity is mediated by high-affinity interaction with the glycosphingolipid receptor (Gb3) on host cells.
Purpose of the Study:
- To investigate the mechanism of Shiga toxin action.
- To explore potential therapeutic interventions for Stx-associated diseases.
- To evaluate the efficacy of Stx receptor-based oral therapies.
Main Methods:
- Studied the enzymatic activity of Stx on eukaryotic ribosomes.
- Investigated the role of Gb3 receptor in Stx cell targeting.
- Developed and tested orally administered particles with immobilized Stx receptors.
Main Results:
- Confirmed Stx as potent inhibitors of protein synthesis.
- Demonstrated Gb3 receptor's critical role in Stx-mediated cell entry and toxicity.
- Showcased the potential of oral Stx receptor-based interventions in experimental models.
Conclusions:
- Shiga toxins are highly potent protein synthesis inhibitors crucial in bacterial pathogenesis.
- Gb3 receptor interactions are key to Stx's cellular targeting and disease manifestation.
- Oral administration of immobilized Stx receptors presents a promising therapeutic avenue for Stx-induced diseases.