Helicobacter pylori–binding nonacid glycosphingolipids in the human stomach

Abstract

Edited by Chris WhitfieldHelicobacter pylori has a number of well-characterized carbohydrate-binding adhesins (BabA, SabA, and LabA) that promote adhesion to the gastric mucosa. In contrast, information on the glycoconjugates present in the human stomach remains unavailable. Here, we used MS and binding of carbohydraterecognizing ligands to characterize the glycosphingolipids of three human stomachs from individuals with different blood group phenotypes (O(Rh؊)P, A(Rh؉)P, and A(Rh؉)p), focusing on compounds recognized by H. pylori. We observed a high degree of structural complexity, and the composition of glycosphingolipids differed among individuals with different blood groups. The type 2 chain was the dominating core chain of the complex glycosphingolipids in the human stomach, in contrast to the complex glycosphingolipids in the human small intestine, which have mainly a type 1 core. H. pylori did not bind to the O(Rh؊)P stomach glycosphingolipids, whose major complex glycosphingolipids were neolactotetraosylceramide, the Le x , Le a , and H type 2 pentaosylceramides, and the Le y hexaosylceramide. Several H. pylori-binding compounds were present among the A(Rh؉)P and A(Rh؉)p stomach glycosphingolipids. Ligands for BabA-mediated binding of H. pylori were the Le b hexaosylceramide, the H type 1 pentaosylceramide, and the A type 1/ALe b heptaosylceramide. Additional H. pylori-binding glycosphingolipids recognized by BabA-deficient strains were lactosylceramide, lactotetraosylceramide, the x 2 pentaosylceramide, and neolactohexaosylceramide. Our characterization of human gastric receptors required for H. pylori adhesion provides a basis for the development of specific compounds that inhibit the binding of this bacterium to the human gastric mucosa.

Characterization of glycosphingolipids from gastrointestinal stromal tumours

“…MS 2 of the molecular ion at m/z 1201 (Fig. 8 I) gave a spectrum that was very similar to the MS 2 spectrum obtained from reference blood group type 1/ALe b heptasaccharide 18 . The series of C-type fragment ions (C 2 at m/z 528, C 3 at m/z 877, and C 4 at m/z 1039) demonstrated a HexNAc-(Fuc-)Hex-(Fuc-)HexNAc-Hex-Hex sequence.…”

“…9E), was present, and the C 3 /Z 3 β ion at m/z 713 identified an internal 4-linked GlcNAc substituted with a Fuc at 3-position 17 . This MS 2 spectrum and the MS 2 spectrum of reference blood group A type 2/ALe y heptasaccharide 18 were very similar.…”

“…*marks a non-oligosaccharide contaminant. www.nature.com/scientificreports/ Overall the glycosphingolipid patterns of the three gastric GISTs had a high similarity with the glycosphingolipids of the human stomach 18,27 . The non-acid glycosphingolipids of human stomach had a high degree of structural complexity, and the composition of glycosphingolipids differed for individuals of separate blood groups.…”

“…The native glycosphingolipid fractions were analyzed by LC-ESI/MS as described 18,40 . Aliquots of the glycosphingolipid fractions were dissolved in methanol:acetonitrile 75:25 (by volume) and separated on a 200 × 0.250 mm column, packed in-house with 5 µm polyamine II particles (YMC Europe GmbH, Dinslaken, Germany).…”

“…The glycosphingolipid-derived oligosaccharides were resuspended in 50 µl water and analyzed by LC-ESI/ MS as described 16,18,40 . The oligosaccharides were separated on a column (100 × 0.250 mm) packed in-house with 5 µm porous graphite particles (Hypercarb, Thermo-Hypersil, Runcorn, UK).…”