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Infiltration of neutrophils and monocytes into the gastric mucosa is a hallmark of chronic gastritis caused by Helicobacter pylori. Certain H. pylori strains nonopsonized stimulate neutrophils to production of reactive oxygen species causing oxidative damage of the gastric epithelium. Here, the contribution of some H. pylori virulence factors, the blood group antigen-binding adhesin BabA, the sialic acid-binding adhesin SabA, the neutrophil-activating protein HP-NAP, and the vacuolating cytotoxin VacA, to the activation of human neutrophils in terms of adherence, phagocytosis, and oxidative burst was investigated. Neutrophils were challenged with wild type bacteria and isogenic mutants lacking BabA, SabA, HP-NAP, or VacA. Mutant and wild type strains lacking SabA had no neutrophil-activating capacity, demonstrating that binding of H. pylori to sialylated neutrophil receptors plays a pivotal initial role in the adherence and phagocytosis of the bacteria and the induction of the oxidative burst. The link between receptor binding and oxidative burst involves a G-proteinlinked signaling pathway and downstream activation of phosphatidylinositol 3-kinase as shown by experiments using signal transduction inhibitors. Collectively our data suggest that the sialic acid-binding SabA adhesin is a prerequisite for the nonopsonic activation of human neutrophils and, thus, is a virulence factor important for the pathogenesis of H. pylori infection.

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“…2B. As reported previously (21), the bacteria bound to several proteins with apparent relative molecular masses between 40 and 70 kDa.…”

Section: Binding Of H Pylori To Human Neutrophil Gangliosides Issupporting

confidence: 74%

“…Several of these H. pylori-binding gangliosides are also present in human neutrophils (19,20). In addition, some H. pylori strains bind to polyglycosylceramides and glycoproteins of human neutrophils in a sialic acid-dependent binding manner (21).…”

mentioning

confidence: 99%

The Sialic Acid Binding SabA Adhesin of Helicobacter pylori Is Essential for Nonopsonic Activation of Human Neutrophils

Unemo

Aspholm-Hurtig

Ilver

et al. 2005

Journal of Biological Chemistry

107

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“…In most of the experiments four strains, the type strains CCUG 17874 and 17875 (obtained from Culture Collection, University of Göteborg, (CCUG), Sweden, and the clinical isolates S-002, and S-032, were used in parallel. 1 The glycosphingolipid nomenclature follows the recommendations by the IUPAC-IUB Commission on Biochemical Nomenclature ( [13][14][15][16][17][18]. It is assumed that Gal, Glc, GlcNAc, GalNAc, NeuAc, and NeuGc are of the D-configuration, Fuc of the L-configuration, and all sugars present in the pyranose form.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, the binding of the bacterium to such diverse compounds as phosphatidylethanolamine and gangliotetraosylceramide (7), the Le b blood group determinant (8), heparan sulfate (9), the GM3 1 ganglioside and sulfatide (10,11), and lactosylceramide (12), has been reported. A sialic aciddependent binding of H. pylori to large complex glycosphingolipids (polyglycosylceramides) has also been documented (13). However, only one H. pylori adhesin, the Le b binding BabA adhesin, has been identified to date (14).…”

mentioning

confidence: 99%

Lactotetraosylceramide, a Novel Glycosphingolipid Receptor for Helicobacter pylori, Present in Human Gastric Epithelium

Teneberg

Leonardsson

Karlsson

et al. 2002

Journal of Biological Chemistry

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The binding of Helicobacter pylori to glycosphingolipids was examined by binding of 35 S-labeled bacteria to glycosphingolipids on thin-layer chromatograms. In addition to previously reported binding specificities, a selective binding to a non-acid tetraglycosylceramide of human meconium was found. This H. pylori binding glycosphingolipid was isolated and, on the basis of mass spectrometry, proton NMR spectroscopy, and degradation studies, were identified as Gal␤3GlcNAc␤3-Gal␤4Glc␤1Cer (lactotetraosylceramide). When using non-acid glycosphingolipid preparations from human gastric epithelial cells, an identical binding of H. pylori to the tetraglycosylceramide interval was obtained in one of seven samples. Evidence for the presence of lactotetraosylceramide in the binding-active interval was obtained by proton NMR spectroscopy of intact glycosphingolipids and by gas chromatography-electron ionization mass spectrometry of permethylated tetrasaccharides obtained by ceramide glycanase hydrolysis. The lactotetraosylceramide binding property was detected in 65 of 74 H. pylori isolates (88%). Binding of H. pylori to lactotetraosylceramide on thin-layer chromatograms was inhibited by preincubation with lactotetraose but not with lactose. Removal of the terminal galactose of lactotetraosylceramide by galactosidase hydrolysis abolished the binding as did hydrazinolysis of the acetamido group of the Nacetylglucosamine. Therefore, Gal␤3GlcNAc is an essential part of the binding epitope.Adhesion of microorganisms to target cells is regarded as a first step in pathogenesis of infections, where the specificity of the adhesins of the infectious agent on the one hand and the receptor structures expressed by the epithelial cells of the host target organ on the other are important determinants of the host range and the tissue tropism of the pathogen (1).The human gastric pathogen Helicobacter pylori is an etiologic agent of chronic active gastritis, peptic ulcer disease, and gastric adenocarcinoma (2, 3). This Gram-negative bacterium has a very distinct host range and tissue tropism, i.e. it requires human gastric epithelium for colonization (4). In the human stomach most of the bacteria are found in the mucus layer (5), but selective association of the bacteria to surface mucous cells has also been shown (4, 6).Several different binding specificities of H. pylori have previously been demonstrated. Thus, the binding of the bacterium to such diverse compounds as phosphatidylethanolamine and gangliotetraosylceramide (7), the Le b blood group determinant (8), heparan sulfate (9), the GM3 1 ganglioside and sulfatide (10, 11), and lactosylceramide (12), has been reported. A sialic aciddependent binding of H. pylori to large complex glycosphingolipids (polyglycosylceramides) has also been documented (13). However, only one H. pylori adhesin, the Le b binding BabA adhesin, has been identified to date (14).In the present study a number of different H. pylori strains were labeled with [35 S]methionine and examined for binding to a panel of...

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“…Sias are also known to be targets for a variety of microbial proteins involved in host cell recognition, e.g. the influenza virus hemagglutinin (11) and one of the adhesins of Helicobacter pylori (12)(13)(14). The Sia molecule can be modified by the addition of O-acetyl esters on the hydroxyl-groups of the 4, 7, 8, and 9 positions (2).…”

mentioning

confidence: 99%

Lysosomal and Cytosolic Sialic Acid 9-O-Acetylesterase Activities Can Be Encoded by One Gene via Differential Usage of a Signal Peptide-encoding Exon at the N Terminus

Takematsu¹,

Díaz²,

Stoddart³

et al. 1999

Journal of Biological Chemistry

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9-O-Acetylation is one of the most common modifications of sialic acids, and it can affect several sialic acidmediated recognition phenomena. We previously reported a cDNA encoding a lysosomal sialic acid-specific 9-O-acetylesterase, which traverses the endoplasmic reticulum-Golgi pathway and localizes primarily to lysosomes and endosomes. In this study, we report a variant cDNA derived from the same gene that contains a different 5 region. This cDNA has a putative open reading frame lacking a signal peptide-encoding sequence and is thus a candidate for the previously described cytosolic sialic acid 9-O-acetylesterase activity. Epitope-tagged constructs confirm that the new sequence causes the protein product to be targeted to the cytosol and has esterase activity. Using reverse transcription-polymerase chain reaction to distinguish the two forms of message, we show that although the lysosomal sialic acidspecific 9-O-acetylesterase message has a widespread pattern of expression in adult mouse tissues, this cytosolic sialic acid 9-O-acetylesterase form has a rather restricted distribution, with the strongest expression in the liver, ovary, and brain. Using a polyclonal antibody directed against the 69-amino acid region common to both proteins, we confirmed that the expression of glycosylated and nonglycosylated polypeptides occurred in appropriate subcellular fractions of normal mouse tissues. Rodent liver polypeptides reacting to the antibody also co-purify with previously described lysosomal sialic acid esterase activity and at least a portion of the cytosolic activity. Thus, two sialic acid 9-O-acetylesterases found in very different subcellular compartments can be encoded by a single gene by differential usage of a signal peptide-encoding exon at the N terminus. The 5-rapid amplification of cDNA ends results and the differences in tissue-specific expression suggest that expression of these two products may be differentially regulated by independent promoters.

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Cited by 39 publications

References 26 publications

The Sialic Acid Binding SabA Adhesin of Helicobacter pylori Is Essential for Nonopsonic Activation of Human Neutrophils

The Sialic Acid Binding SabA Adhesin of Helicobacter pylori Is Essential for Nonopsonic Activation of Human Neutrophils

Lactotetraosylceramide, a Novel Glycosphingolipid Receptor for Helicobacter pylori, Present in Human Gastric Epithelium

Lysosomal and Cytosolic Sialic Acid 9-O-Acetylesterase Activities Can Be Encoded by One Gene via Differential Usage of a Signal Peptide-encoding Exon at the N Terminus

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