| 1. |
- Hood, Derek W., et al.
(author)
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Genes required for the synthesis of heptose-containing oligosaccharide outer core extensions in Haemophilus influenzae lipopolysaccharide
- 2010
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In: Microbiology. - : Microbiology Society. - 1350-0872 .- 1465-2080. ; 156, s. 3421-3431
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Journal article (peer-reviewed)abstract
- Heptose-containing oligosaccharides (OSs) are found in the outer core of the lipopolysaccharide (LPS) of a subset of non-typable Haemophilus influenzae (NTHi) strains. Candidate genes for the addition of either L-glycero-D-manno-heptose (LD-Hep) or D-glycero-D-manno-heptose (DD-Hep) and subsequent hexose sugars to these OSs have been identified from the recently completed genome sequences available for NTHi strains. losA1/losB1 and losA2/losB2 are two sets of related genes in which losA has homology to genes encoding glycosyltransferases and losB to genes encoding heptosyltransferases. Each set of genes is variably present across NTHi strains and is located in a region of the genome with an alternative gene organization between strains that contributes to LPS heterogeneity. Dependent upon the strain background, the LPS phenotype, structure and serum resistance of strains mutated in these genes were altered when compared with the relevant parent strain. Our studies confirm that losB1 and losB2 usually encode DD-heptosyl- and LD-heptosyl transferases, respectively, and that losA1 and losA2 encode glycosyltransferases that play a role in OS extensions of NTHi LPS.
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| 2. |
- Houliston, R. Scott, et al.
(author)
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A Haemophilus influenzae strain associated with fisher syndrome expresses a novel disialylated ganglioside mimic
- 2007
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In: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 46:27, s. 8164-8171
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Journal article (peer-reviewed)abstract
- The non-typeable Haemophilus influenzae strain DH1 was isolated from a 25 year old male patient with Fisher syndrome, a postinfectious autoimmune condition characterized by the presence of anti-GQ1b IgG antibodies that target and initiate damage to peripheral nerves. DH1 was found to display an alpha NeuAc(2-8)alpha NeuAc(2-3)beta Gal branch bound to the tetraheptosyl backbone core of its lipooligosaccharide (LOS). The novel sialylation pattern was found to be dependent on the activity of a bifunctional sialyltransferase, Lic3B, which catalyzes the addition of both the terminal and subterminal sialic acid residues. Patient serum IgGs bind to DH1 LOS, and the reactivity is significantly influenced by the presence of sialylated glycoforms. The display by DH1, of a surface glycan that mimics the terminal trisaccharide portion of disialosyl-containing gangliosides, provides strong evidence for its involvement in the development of Fisher syndrome.
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| 3. |
- Issa, Samah, et al.
(author)
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Higher Energy Collisional Dissociation Mass Spectrometry of Sulfated O-Linked Oligosaccharides
- 2018
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In: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 17:9, s. 3259-3267
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Journal article (peer-reviewed)abstract
- Sulfation is the final decoration of mucin-type O-linked oligosaccharides before mucins are released into the lumen of the gastrointestinal, respiratory, and genital tracts. Because only a fraction of oligosaccharides undergo this type of modifications in the Golgi apparatus, sometimes also only by dedicated cells, the glycobiology of these low abundant sulfated oligosaccharides is often overlooked. At the same time, the technology to consistently identify and characterize them has been lagging. We adopted higher energy collisional dissociation to characterize sulfated oligosaccharides from porcine gastric and human salivary MUC5B mucins. With this approach we could generate conclusive spectra up to nonasaccharides. Both singly and doubly sulfated oligosaccharides were characterized. By comparing the fragmentation of low-mass fragments of m/z 100-320 with standards for six-linked and three linked sulfate, it could be shown that characteristic fragmentation exists, verifying that porcine gastric mucin contains mostly six linked sulfate to GlcNAc, whereas human MUC5B contains mostly three-linked Gal. When performing ion-trap MS2 fragmentation, these low-molecular-mass fragments are usually not detected. Hence it can be concluded that to be able to address biological questions of sulfation low-mass fragments are important for the assignment of sulfate position.
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| 4. |
- Jin, Chunsheng, et al.
(author)
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Structural diversity of human gastric mucin glycans.
- 2017
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In: Molecular & cellular proteomics : MCP. - 1535-9484.
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Journal article (peer-reviewed)abstract
- The mucin O-glycosylation of 10 individuals with and without gastric disease was examined in depth in order to generate a structural map of human gastric glycosylation. In the stomach, these mucins and their O-glycosylation protect the epithelial surface from the acidic gastric juice and provide the first point of interaction for pathogens such as Helicobacter pylori, reported to cause gastritis, gastric and duodenal ulcers and gastric cancer. The rational of the present study was to map the O-glycosylation that the pathogen may come in contact with. An enormous diversity in glycosylation was found, which varied both between individuals and within mucins from a single individual: mucin glycan chain length ranged from 2-13 residues, each individual carried 34-103 O-glycan structures and in total over 258 structures were identified. The majority of gastric O-glycans were neutral and fucosylated. Blood group I antigens, as well as terminal α1,4-GlcNAc-like and GalNAcβ1-4GlcNAc-like (LacdiNAc-like), were common modifications of human gastric O-glycans. Furthemore, each individual carried 1-14 glycan structures that were unique for that individual. The diversity and alterations in gastric O-glycosylation broaden our understanding of the human gastric O-glycome and its implications for gastric cancer research and emphasize that the high individual variation makes it difficult to identify gastric cancer specific structures. However, despite the low number of individuals, we could verify a higher level of sialylation and sulfation on gastric O-glycans from cancerous tissue than from healthy stomachs.
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| 5. |
- Mateoiu, Constantina, et al.
(author)
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Analysis of blood group antigens on MUC5AC in mucinous ovarian cancer tissues using in situ proximity ligation assay.
- 2021
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In: Glycobiology. - : Oxford University Press (OUP). - 1460-2423. ; 31:11, s. 1464-1471
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Journal article (peer-reviewed)abstract
- MUC5AC has been indicated to be a marker for mucinous ovarian cancer (OC). We investigated the use of in situ proximity ligation assay (PLA) for blood group ABH expressing MUC5AC to differentiate between serous and mucinous OC, to validate preceding observations that also MUC5AC ABH expression is increased in mucinous OC. We developed PLA for anti-A, B, and H/anti-MUC5AC and a PLA using a combined lectin Ulex europaeus agglutinin I (UEA I)/anti-MUC5AC assay. The PLAs were verified with mass spectrometry, where mucinous OC secretor positive patients' cysts fluids containing ABH O-linked oligosaccharides also showed positive OC tissue PLA staining. A nonsecretor mucinous OC cyst fluid was negative for ABH and displayed negative PLA staining of the matched tissue. Using the UEA I/MUC5AC PLA, we screened a tissue micro array of 410 ovarian tissue samples from patients with various stages of mucinous or serous OC, 32 samples with metastasis to the ovaries and 34 controls. The PLA allowed differentiating mucinous tumors with a sensitivity of 84% and a specificity of 97% both against serous cancer but also compared to tissues from controls. This sensitivity is close to the expected incidence of secretor individuals in a population. The recorded sensitivity was also found to be higher compared to mucinous type cancer with metastasis to the ovaries, where only 32% were positive. We conclude that UEA 1/MUC5AC PLA allows glycospecific differentiation between serous and mucinous OC in patients with positive secretor status and will not identify secretor negative individuals with mucinous OC.
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| 6. |
- Peturova, M., et al.
(author)
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Structural features of the O-antigen of Rickettsia typhi, the etiological agent of endemic typhus
- 2015
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In: Acta Virologica. - : AEPress, s.r.o.. - 0001-723X .- 1336-2305. ; 59:3, s. 228-233
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Journal article (peer-reviewed)abstract
- Elucidation of the O-specific polysaccharide chain of lipopolysaccharide (LPS) from Rickettsia typhi, the etiological agent of endemic typhus, is described. Structural information was established by a combination of monosaccharide and methylation analyses of the O-chain, and by mass (MS) and nuclear magnetic resonance (NMR) spectrometries of oligosaccharides arised through its hydrofluoric (HF) acid degradation. Based on the combined data from these experiments, two major polymer populations of the O-specific chain have been determined with the following structural features: alpha-L-QuiNAc-(1 -> 4)-[alpha-D-Glc-(1 -> 3)-alpha-L-QuiNAc-(1 -> 4)](n) -alpha-D-Glc-(1 -> 4)-alpha-D-Glc ->,alpha-D-Glc-(1 -> 3)-alpha-L-QuiNAc-(1 -> 4)-[alpha-D-Glc-(1 -> 3)-alpha-L-QuiNAc-(1 -> 4)](n)-alpha-D-Glc ->. The linear backbone is most probably flanked with short side chains of D-GlcNAc-(1 -> 3)-alpha-L-QuiNAc-(1 -> 3)-D-GlcNAc -> that are attached to it via L-QuiNAc as a branching point. It is suggested that a dimer alpha-L-QuiNAc-(1 -> 3)-alpha-D-GlcNAc may represent a common epitope in the O-antigens of Proteus vulgaris OX19 and R. typhi responsible for the observed serological cross-reactivity.
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| 7. |
- Thomsson, Kristina A, 1969, et al.
(author)
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Sulfation of O-glycans on Mucin-type Proteins From Serous Ovarian Epithelial Tumors.
- 2021
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In: Molecular & cellular proteomics : MCP. - : Elsevier BV. - 1535-9484 .- 1535-9476. ; 20
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Journal article (peer-reviewed)abstract
- Despite sulfated O-linked glycans being abundant on ovarian cancer (OC) glycoproteins, their regulation during cancer development and involvement in cancer pathogenesis remain unexplored. We characterized O-glycans carrying sulfation on galactose residues and compared their expression with defined sulfotransferases regulated during OC development. Desialylated sulfated oligosaccharides were released from acidic glycoproteins in the cyst fluid from one patient with a benign serous cyst and one patient with serous OC. Oligosaccharides characterized by LC-MSn were identified as core 1 and core 2 O-glycans up to the size of decamers and with 1 to 4 sulfates linked to GlcNAc residues and to C-3 and/or C-6 of Gal. To study the specificity of the potential ovarian sulfotransferases involved, Gal3ST2 (Gal-3S)-, Gal3ST4 (Gal-3S)-, and CHST1 (Gal-6S)-encoding expression plasmids were transfected individually into CHO cells also expressing the P-selectin glycoprotein ligand-1/mouse immunoglobulin G2b (PSGL-1/mIg G2b) fusion protein and the human core 2 transferase (GCNT1). Characterization of the PSGL-1/mIg G2b O-glycans showed that Gal3ST2 preferentially sulfated Gal on the C-6 branch of core 2 structures and Gal3ST4 preferred Gal on the C-3 branch independently if core-1 or -2. CHST1 sulfated Gal residues on both the C-3 (core 1/2) and C-6 branches of core 2 structures. Using serous ovarian tissue micro array, Gal3ST2 was found to be decreased in tissue classified as malignant compared with tissues classified as benign or borderline, with the lowest expression in poorly differentiated malignant tissue. Neither Gal3ST4 nor CHST1 was differentially expressed in benign, borderline, or malignant tissue, and there was no correlation between expression level and differentiation stage. The data displays a complex sulfation pattern of O-glycans on OC glycoproteins and that aggressiveness of the cancer is associated with a decreased expression of the Gal3ST2 transferase.
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| 8. |
- Vitiazeva, Varvara, et al.
(author)
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A novel branching pattern in the lipopolysaccharide expressed by non-typeable Haemophilus influenzae strain 1232
- 2013
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In: Carbohydrate Research. - : Elsevier. - 0008-6215 .- 1873-426X. ; 378, s. 114-122
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Journal article (peer-reviewed)abstract
- We report the novel branching pattern in lipopolysaccharide (LPS) expressed by non-typeable Haemophilus influenzae (NTHi) strain 1232. The strain expressed the beta-D-Glcp-(1 -andgt; 4)-[alpha-D-Galp-(1 -andgt; 4)-beta-D-Galp-(1 -andgt; 7)]-D-alpha-D-Hepp-(1 -andgt; 6)-beta-D-Glcp chain linked to the proximal heptose (HepI) of the conserved triheptosyl inner-core moiety of NTHi LPS: L-alpha-D-HepIIIp-(1 -andgt; 2)-[PEtn -andgt; 6]-L-alpha-D-HepIIp-(1 -andgt; 3)-L-alpha-D-HepIp-(1 -andgt; 5)-[PPEtn -andgt; 4]-alpha-Kdop-(2 -andgt; 6)-lipid A. The structure has been elucidated using NMR spectroscopy, electrospray ionization mass spectrometry (ESI-MS) and capillary electrophoresis coupled to electrospray ionization tandem mass spectrometry (CE-ESI-MSn) on O-deacylated LPS and core oligosaccharide (OS) materials, as well as HPLC-ESI-MSo on permethylated, dephosphorylated OS. It was also found that a tetrasaccharide unit bearing sialic acid [alpha-Neu5Ac-(2 -andgt; 3)-beta-D-Galp-(1 -andgt; 4)-beta-D-GlcNAcp-(1 -andgt; 3)-beta-D-Galp-(1 -andgt;] could substitute O-4 of the beta-D-Glcp linked to HepI. In addition, the distal heptose (HepIII) was substituted by PCho -andgt; 6-beta-D-Galp-(1 -andgt; at the O-2 position.
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| 9. |
- Vitiazeva, Varvara
(author)
-
Structural studies of lipopolysaccharides expressed by non-typeable Haemophilus influenzae and Haemophilus parainfluenzae strains
- 2012
-
Doctoral thesis (other academic/artistic)abstract
- The present thesis describes lipopolysaccharide (LPS) structures expressed by non-typeable Haemophilus influenzae and Haemophilus parainfluenzae strains. LPS is a major surface component of Gram-negative bacteria. Structural studies of LPS are very important for understanding the adaptive mechanisms which help bacteria to survive in the host environment. Non-typeable Haemophilus influenzae (NTHi) is a common human commensal of the nasopharynx. It is also pathogenic and causes both acute and chronic diseases, such as otitis media, sinusitis, pneumonia and bronchitis. H. influenzae expresses rough type LPS (lacking O-antigen), which is implicated as a major virulence factor. 25 NTHi otitis media isolates were selected for structural studies of LPS. These clinical isolates represent the structural diversity of LPS in the natural population. Structural studies of H. influenzae LPS have resulted in a molecular model consisting of a conserved (PEtn)-substituted triheptosyl inner-core moiety (HepI–HepII-HepIII) in which each of the heptose residues can provide a point for elongation by oligosaccharide chains (outer-core region). NTHi strains 1158/1159 and 1232, described in this thesis, were selected from this collection of clinical isolates. These strains express additional D,D-Hep residue in the outer-core region of LPS. Haemophilus parainfluenzae is a part of normal human flora. Previous studies have indicated that H. parainfluenzae expresses LPS structures that are very similar to those expressed by H. influenzae. On the other hand some H. parainfluenzae strains express O-antigen containing LPS. The structures of the O-antigen from H. parainfluenzae strains 20 and 16 are described in this thesis. The structural investigations of LPS of H. influenzae and the comparison with LPS expressed by H. parainfluenzae will increase the knowledge of biological properties of LPS and its role in bacterial virulence.
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| 10. |
- Vitiazeva, Varvara, et al.
(author)
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The O-Linked Glycome and Blood Group Antigens ABO on Mucin-Type Glycoproteins in Mucinous and Serous Epithelial Ovarian Tumors
- 2015
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In: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:6
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Journal article (peer-reviewed)abstract
- Background Mucins are heavily O-glycosylated proteins where the glycosylation has been shown to play an important role in cancer. Normal epithelial ovarian cells do not express secreted mucins, but their abnormal expression has previously been described in epithelial ovarian cancer and may relate to tumor formation and progression. The cyst fluids were shown to be a rich source for acidic glycoproteins. The study of these proteins can potentially lead to the identification of more effective biomarkers for ovarian cancer. In this study, we analyzed the expression of the MUC5AC and the O-glycosylation of acidic glycoproteins secreted into ovarian cyst fluids. The samples were obtained from patients with serous and mucinous ovarian tumors of different stages (benign, borderline, malignant) and grades. The O-linked oligosaccharides were released and analyzed by negative-ion graphitized carbon Liquid Chromatography (LC) coupled to Electrospray Ionization tandem Mass Spectrometry (ESI-MSn). The LC-ESI-MSn of the oligosaccharides from ovarian cyst fluids displayed differences in expression of fucose containing structures such as blood group ABO antigens and Lewis-type epitopes. The obtained data showed that serous and mucinous benign adenomas, mucinous low malignant potential carcinomas (LMPs, borderline) and mucinous low-grade carcinomas have a high level of blood groups and Lewis type epitopes. In contrast, this type of fucosylated structures were low abundant in the high-grade mucinous carcinomas or in serous carcinomas. In addition, the ovarian tumors that showed a high level of expression of blood group antigens also revealed a strong reactivity towards the MUC5AC antibody. To visualize the differences between serous and mucinous ovarian tumors based on the O-glycosylation, a hierarchical cluster analysis was performed using mass spectrometry average compositions (MSAC). Mucinous benign and LMPs along with mucinous low-grade carcinomas appear to be different from serous and high-grade mucinous carcinomas based on their O-glycan profiles.
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