| 1. |
- Fagerberg, David, et al.
(författare)
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Novel Leb-like Helicobacter pylori-binding glycosphingolipid created by the expression of human alpha-1,3/4-fucosyltransferase in FVB/N mouse stomach.
- 2009
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 1460-2423 .- 0959-6658. ; 19:2, s. 182-91
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Tidskriftsartikel (refereegranskat)abstract
- The "Le(b) mouse" was established as a model for investigations of the molecular events following Le(b)-mediated adhesion of Helicobacter pylori to the gastric epithelium. By the expression of a human alpha-1,3/4-fucosyltransferase in the gastric pit cell lineage of FVB/N transgenic mice, a production of Le(b) glycoproteins in gastric pit and surface mucous cells was obtained in this "Le(b) mouse," as demonstrated by binding of monoclonal anti-Le(b) antibodies. To explore the effects of the human alpha-1,3/4-fucosyltransferase on glycosphingolipid structures, neutral glycosphingolipids were isolated from stomachs of transgenic alpha-1,3/4-fucosyltransferase-expressing mice. A glycosphingolipid recognized by BabA-expressing H. pylori was isolated and characterized by mass spectrometry and proton NMR as Fuc alpha 2Gal beta 3(Fuc alpha 4)GalNAc beta 4 Gal beta 4 Glc beta 1Cer, i.e., a novel Le(b)-like glycosphingolipid on a ganglio core. In addition, two other novel glycosphingolipids were isolated from the mouse stomach epithelium that were found to be nonbinding with regard to H. pylori. The first was a pentaglycosylceramide, GalNAc beta 3 Gal alpha 3(Fuc alpha 2)Gal beta 4 Glc beta 1Cer, in which the isoglobotetrasaccharide has been combined with Fuc alpha 2 to yield an isoglobotetraosylceramide with an internal blood group B determinant. The second one was an elongated fucosyl-gangliotetraosylceramide, GalNAc beta 3(Fuc alpha 2)Gal beta 3GalNAc beta 4Gal beta 4 Glc beta 1Cer.
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| 2. |
- Gustafsson, A., et al.
(författare)
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Carbohydrate-dependent inhibition of Helicobacter pylori colonization using porcine milk
- 2006
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 0959-6658 .- 1460-2423. ; 16:1, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Breast milk has a well-known anti-microbial effect, which is in part due to the many different carbohydrate structures expressed. This renders it a position as a potential therapeutic for treatment of infection by different pathogens, thus avoiding the drawbacks of many antibiotics. In a previous study, we showed that pigs express the Helicobacter pylori receptors, sialyl Lewis x (Le x) and Le b, on various milk proteins. Here, we investigate the pig breed- and individual-specific expression of these epitopes, as well as the inhibitory capacity of porcine milk on H. pylori binding and colonization. Milk proteins from three different pig breeds were analysed by western blotting using antibodies with known carbohydrate specificity. An adhesion assay was used to investigate the capacity of pig milk to inhibit H. pylori binding to neoglycoproteins carrying Le b and sialyl-di-Le x. alpha1,3/4-fucosyltransferase transgenic FVB/N mice, known to express Le b and sialyl Le x in their gastric epithelium, were colonized by H. pylori and were subsequently treated with Le b- and sialyl Le x-expressing or nonexpressing porcine milk, or water (control) only. The degree of H. pylori colonization in the different treatment groups was quantified. The expression of the Le b and sialyl Le x carbohydrate epitopes on pig milk proteins was breed- and individual specific and correlated to the ability of porcine milk to inhibit H. pylori adhesion in vitro and H. pylori colonization in vivo. Milk from certain pig breeds may have a therapeutic and/or prophylactic effect on H. pylori infection.
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| 3. |
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| 4. |
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| 5. |
- Löfling, Jonas, et al.
(författare)
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Studies of Lewis antigens and H. pylori adhesion in CHO cell lines engineered to express Lewis b determinants.
- 2008
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 1460-2423 .- 0959-6658. ; 18:7, s. 494-501
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Tidskriftsartikel (refereegranskat)abstract
- Many microbes bind and adhere via adhesins to host cell carbohydrates as an initial step for infection. Therefore, cell lines expressing Lewis b (Le(b)) determinants were generated as a potential model system for Helicobacter pylori colonization and infection, and their expression of blood group Lewis determinants was characterized. CHO-K1 cells were stably transfected with selected glycosyltransferase cDNAs, and two Le(b) positive clones, 1C5 and 2C2, were identified. Expression of Lewis (Le(a), Le(b), Le(x), and Le(y)) determinants was analyzed by flow cytometry of intact cells, SDS-PAGE/Western blot of solubilized glycoproteins, and thin layer chromatography immunostaining of isolated glycolipids (GL). Binding of H. pylori to cells was examined by microscopy and quantified. Flow cytometry showed that 1C5 and 2C2 were Le(a) and Le(b) positive. 1C5 expressed Le(b) on O-linked, but not N-linked, glycans and only weakly on GLs. In contrast, 2C2 expressed Le(b) on N-, O-glycans, and GLs. Furthermore, both clones expressed Le(a) on N- and O-glycans but not on GLs. 2C2, but not 1C5, stained positively for Le(y) on N-linked glycans and GLs. Both clones, as well as the parental CHO-K1 cells, expressed Le(x) on GLs. A Le(b)-binding H. pylori strain bound to the 1C5 and 2C2 cells. In summary, two glycosyltransferase transfected CHO-K1 cell clones differed regarding Lewis antigen expression on N- and O-linked glycans as well as on GLs. Both clones examined supported adhesion of a Le(b)-binding H. pylori strain and may thus be a useful in vitro model system for H. pylori colonization/infection studies.
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| 6. |
- Magalhães, Ana, et al.
(författare)
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Fut2-null mice display an altered glycosylation profile and impaired BabA-mediated Helicobacter pylori adhesion to gastric mucosa
- 2009
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 0959-6658 .- 1460-2423. ; 19:12, s. 1525-1536
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Tidskriftsartikel (refereegranskat)abstract
- Glycoconjugates expressed on gastric mucosa play a crucial role in host-pathogen interactions. The FUT2 enzyme catalyzes the addition of terminal alpha(1,2)fucose residues, producing the H type 1 structure expressed on the surface of epithelial cells and in mucosal secretions of secretor individuals. Inactivating mutations in the human FUT2 gene are associated with reduced susceptibility to Helicobacter pylori infection. H. pylori infects over half the world's population and causes diverse gastric lesions, from gastritis to gastric cancer. H. pylori adhesion constitutes a crucial step in the establishment of a successful infection. The BabA adhesin binds the Le(b) and H type 1 structures expressed on gastric mucins, while SabA binds to sialylated carbohydrates mediating the adherence to inflamed gastric mucosa. In this study, we have used an animal model of nonsecretors, Fut2-null mice, to characterize the glycosylation profile and evaluate the effect of the observed glycan expression modifications in the process of H. pylori adhesion. We have demonstrated expression of terminal difucosylated glycan structures in C57Bl/6 mice gastric mucosa and that Fut2-null mice showed marked alteration in gastric mucosa glycosylation, characterized by diminished expression of alpha(1,2)fucosylated structures as indicated by lectin and antibody staining and further confirmed by mass spectrometry analysis. This altered glycosylation profile was further confirmed by the absence of Fucalpha(1,2)-dependent binding of calicivirus virus-like particles. Finally, using a panel of H. pylori strains, with different adhesin expression profiles, we have demonstated an impairment of BabA-dependent adhesion of H. pylori to Fut2-null mice gastric mucosa, whereas SabA-mediated binding was not affected.
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| 7. |
- Magalhaes, Ana, et al.
(författare)
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The glycan receptors of Helicobacter pylori : decoding the pathways underlying gastric glycophenotype modulation
- 2016
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Ingår i: Glycobiology. - : Oxford University Press (OUP). - 0959-6658 .- 1460-2423. ; 26:12, s. 1401-1402
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Tidskriftsartikel (refereegranskat)abstract
- The gastrointestinal tract is covered by a complex extracellular mucus layer that protects the gastric epithelium fromexternal aggressions such as chemical agents, microorganismsand shear stress. Although this mucus barrier confers protec-tion against certain pathogens, it may also provide a niche formicrobial binding.Helicobacter pyloriexploits the host glycoconjugates present in the gastric mucus layer and lining thesurface epithelium of the gastric mucosa to colonize the stomach. Infection can persist for decades promoting chronicinflammation, and in a subset of individuals lesions cansilently progress to cancer. The secreted MUC5AC mucin isthe main component of the gastric mucus layer, andH. pyloriBabA-mediated binding to MUC5AC confers increased riskfor overt disease. We have shown that FUT2 determines theO-glycosylation pattern of Muc5ac, with Fut2 knock-outleading to a marked decrease inα1,2-fucosylated structuresand increased expression of the terminal type 1 glycan structure Lewisa. Importantly, for thefirst time, we structurallyvalidated the expression of Lewisain murine gastric mucosa(1). We further demonstrated that loss of mucin FUT2-mediated fucosylation impairs gastric mucosal binding ofH.pyloriBabA adhesin, which is a recognized feature of patho-genicity. UponH. pyloriinfection,concomitantly with tissueinflammation, there is a remodeling of the gastric glycopheno-type. We showed that increased expression of sialyl-Lewisa/xantigens is due to transcriptional up-regulation of theB3GNT5,B3GALT5,andFUT3genes. In addition, weobserved thatH. pyloriinfected individuals present a markedgastric local pro-inflammatory signature with significantlyhigher TNF-αlevels and demonstrated that TNF-induced activation of the NF-kappaB pathway results in B3GNT5 up-regulation (2). Furthermore, we showed that this gastric glycosylation shift, characterized by increased sialylation pat-terns, favors SabA-mediatedH. pyloriattachment to humaninflamed gastric mucosa. Our data provides clinically relevantinsights into the regulatory mechanisms underlyingH. pylorimodulation of host glycosylation machinery, and phenotypicalterations crucial for life-long infection and gastric disease.
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