Escherichia coli STb toxin binding to sulfatide and its inhibition by carragenan

Abstract

Escherichia coli heat-STb is an important cause of diarrhea in piglets. STb was shown to interact specifically with sulfatide (3'-sulfogalactosyl-ceramide) present on the surface of epithelial cells of piglet jejunum. Basic data are lacking on STb binding to sulfatide in solution and more precisely on the possible inhibition of this interaction. Using surface plasmon resonance technology, we compare binding of STb to sulfatide and other glycoshingolipids previously shown, with a multiplate-binding assay, to also interact to various degrees with the enterotoxin. In addition, inhibition of STb-sulfatide binding was studied using free galactose, galactose-sulfate residues and a polymer of sulfated galactans known as carragenan. We determined a dissociation constant of 2.4+/-0.61 nM for the STb-sulfatide interaction. These data indicated that STb was binding to sulfatide with greater affinity than previously determined using radiolabeled toxin. Much lower affinities were observed for lactoceramide and glucoceramide. The binding of STb to sulfatide was clearly inhibited by lambda-carragenan but not by galactose, 4-SO(4)-galactose or 6-SO(4)-galactose. Inhibition of STb binding to its receptor was achieved using lambda-carragenan at picomolar concentrations. Then, using IPEC-J2 cells in culture and flow cytometry, we showed that lambda-carragenan was able to inhibit the permeabilization process associated with STb.

Escherichia coli STb toxin induces apoptosis in intestinal epithelial cell lines

“…However, the affinity of this interaction was described as weak as demonstrated by the kd value of 2-6 +/-1.5  and was partially inhibited by elevated concentrations of charged carbohydrates. The kd value obtained by the authors is in accordance with the value obtained by Chao and Dreyfus (1997) (Goncalves et al, 2008). Thus, carrageenan could represent a molecule that could be used as a prophylactic agent to protect piglets against STb during the post-weaning period.…”

Inhibiting Microbial Toxins Using Plant-Derived Compounds and Plant Extracts

“…These researchers also found an inhibition in the secretory response of the heat-stable toxin in infant mouse [92]. A similar anti-toxic activity with other plant derived compounds namely, oleanolic acid, ursolic acid, and betulinic acid [93], λ-carragenan [94], essential oil from Cymbopogon martini and C. winterianus [95], Psidium guajava [96], thiols and disulfide compounds [97] has been reported.…”

Animal EnterotoxigenicEscherichia coli

“…A mass spectrometer analysis on the lipids isolated following high performance thin layer chromatography of pig jejunum epithelium confirmed the nature of the receptor (473). A dissociation constant of 2.4 ± 0.61 nM for the STb-sulfatide interaction was observed (474). The functionality of sulfatide, a widely distributed acidic glycosphingolipid on the intestinal epithelium, was finally proven in the rat ligated loop assay (472).…”