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Reception of Wnt signals by cells is predominantly mediated by Frizzled receptors in conjunction with a co-receptor, the latter being LRP6 or LRP5 for the Wnt/β-catenin signalling pathway. It is important that cells maintain precise control of receptor activation events in order to properly regulate Wnt/β-catenin signalling as aberrant signalling can result in disease in humans. Phosphorylation of the intracellular domain (ICD) of LRP6 is well known to regulate Wntβ-catenin signalling; however, less is known for regulatory post-translational modification events within the extracellular domain (ECD). Using a cell culture-based expression screen for functional regulators of LRP6, we identified a glycosyltransferase, B3GnT2-like, from a teleost fish (medaka) cDNA library, that modifies LRP6 and regulates Wnt/β-catenin signalling. We provide both gain-of-function and loss-of-function evidence that the single human homolog, B3GnT2, promotes extension of polylactosamine chains at multiple N-glycans on LRP6, thereby enhancing trafficking of LRP6 to the plasma membrane and promoting Wnt/β-catenin signalling. Our findings further highlight the importance of LRP6 as a regulatory hub in Wnt signalling and provide one of the few examples of how a specific glycosyltransferase appears to selectively target a signalling pathway component to alter cellular signalling events. [ABSTRACT FROM AUTHOR]

A combined chemo‐enzymatic synthesis/NMR‐based methodology is presented to identify, in unambiguous manner, the distinctive binding epitope within repeating sugar oligomers when binding to protein receptors. The concept is based on the incorporation of 13C‐labels at specific monosaccharide units, selected within a repeating glycan oligomeric structure. No new chemical tags are added, and thus the chemical entity remains the same, while the presence of the 13C‐labeled monosaccharide breaks the NMR chemical shift degeneracy that occurs in the non‐labeled compound and allows the unique identification of the different components of the oligomer. The approach is demonstrated by a proof‐of‐concept study dealing with the interaction of a polylactosamine hexasaccharide with five different galectins that display distinct preferences for these entities. [ABSTRACT FROM AUTHOR]

Background and Aim: Galectin‐1 plays a protective role against colitis by binding with polylactosamine structures on macrophages in β‐1,4‐galactosyltransferase I‐deficient mice, but the precise function of galectin‐1 remains unknown. In the present study, we investigated the anti‐inflammatory role of galectin‐1 on macrophages to ameliorate ulcerative colitis in both animal model and human tissue samples. Methods: The expression of galectin‐1 in colonic tissues of ulcerative colitis patients was evaluated by immunohistochemistry. Cytokine production of mouse bone marrow‐derived macrophages (BMDMs) cultured with galectin‐1 was investigated. Galectin‐1 binding capacity and polylactosamine expression in macrophages stimulated with lipopolysaccharides were evaluated by flow cytometry. BMDMs cultured with galectin‐1 were transferred into Recombination activating gene (Rag) 2−/− mice, and the severity of the dextran sodium sulfate‐induced colitis model was investigated. Furthermore, RNA sequencing was performed to characterize macrophages treated with galectin‐1. Results: In ulcerative colitis patients, tissue expression of galectin‐1was decreased in inflamed mucosa compared with non‐inflamed mucosa. Galectin‐1 induced interleukin‐10 production in BMDMs, and the interleukin‐10 production was abrogated by lactose, which inhibits the interaction of oligosaccharide–galectin binding. Dextran sodium sulfate colitis was significantly ameliorated in Rag2−/− mice undergoing galectin‐1‐treated BMDM transfer compared with those undergoing vehicle‐treated BMDM transfer. RNA sequencing revealed that treatment with galectin‐1 increased the expression of CCAAT/enhancer binding protein β and CD163, but decreased the expression of CD80 on BMDMs. Conclusion: Galectin‐1, whose expression is decreased in the inflamed mucosa of ulcerative colitis patients, can ameliorate murine colitis by conferring oligosaccharide‐dependent anti‐inflammatory properties to macrophages. [ABSTRACT FROM AUTHOR]

β1,3-N-acetylglucosaminyltransferase (β3GnT8) and β3GnT2 are key enzymes that catalyzes the formation of polylactosamine glycan structures by transferring GlcNAc to tetra-antennary β1-6-branched N-glycan and it also has an important effect on the progression of various types of human cancer. They have been reported to participate in tumor invasion and metastasis by regulating the expression of matrix metalloproteinases (MMPs), CD147, and polylactosamine. However, whether β3GnT8 and β3GnT2 play a role in colorectal cancer and, if so, the underlying mechanisms remain unclear. In our study, we detected the expression of β3GnT8, CD147, MMP2, and galectin3 by immunohistochemistry on 90 paraffin-embedded slices. And β3GnT8, CD147, MMP2, and galectin3 were over-expressed in colorectal cancer tissues. We found that overexpression of β3GnT8 and β3GnT2 promoted invasion of colorectal cancer cells, whereas knockdown of β3GnT8 and β3GnT2 inhibited the invasive activity. Mechanistically, β3GnT8 and β3GnT2 regulated the expression of HG-CD147 and the level of polylactosamines in colorectal cancer cells. Together, these results illustrate that the novel role and the molecular mechanism of β3GnT8 and β3GnT2 in promotion of colorectal cancer invasion. These results suggest that the potential use of β3GnT8 as a tumor target for the therapy of colorectal cancer.

Structural analysis of O-glycans from mucins and characterization of the interaction of these glycans with other biomolecules are essential for a full understanding of mucins. Various techniques have been developed for the structural and functional analysis of glycans. While 9-fluorenylmethyl chloroformate (Fmoc-Cl) is generally used to protect amino groups in peptide synthesis, it can also be used as a glycan-labeling reagent for structural analysis. Fmoc-labeled glycans are strongly fluorescent and can be analyzed with high sensitivity using liquid chromatography-fluorescence detection (LC-FD) analysis as well as being analyzed with high sensitivity by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Fmoc-labeled glycans can be easily delabeled and converted to glycosylamine-form or free (hemiacetal or aldehyde)-form glycans that can be used to fabricate glycan arrays or synthesize glycosyl dendrimers. This derivatization allows for the isolation from biological samples of glycans that are difficult to synthesize chemically, as well as the fabrication of immobilized-glycan devices. The Fmoc labeling method promises to be a tool for accelerating O-glycan structural analysis and an understanding of molecular interactions. In this chapter, we introduce the Fmoc labeling method for analysis of O-glycans and fabrication of O-glycan arrays., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

To reveal O-glycan structures in mucins, it is necessary to release covalently bound O-glycans from the polypeptide backbone and derivatize to a form suitable for structural analysis. Various derivatization methods can now be applied in the analysis of O-glycans following the development of O-glycan release methods. Among the many derivatization methods available, we prefer to use fluorescent labeling with 2-aminobenzoic acid (anthranilic acid, 2AA). 2AA-labeled O-glycans can be detected with high sensitivity using liquid chromatography fluorescence detection (LC-FD) analysis because of the strong fluorescence. In addition, as 2AA has a carboxyl group that carries a negative charge, 2AA-labeled O-glycans can be analyzed with high sensitivity in negative ion mode mass spectrometry. Furthermore, because the negative charge of 2AA provides a driving force for electrophoresis, 2AA-labeled O-glycans can be analyzed using capillary electrophoresis (CE) and capillary affinity electrophoresis. High detection sensitivity and versatility are key advantages of the 2AA-labeling method. Here we present our preferred LC-FD and CE analytical methods for 2AA-labeled O-glycans., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

To elucidate the relationship between the protein function and the diversity and heterogeneity of glycans conjugated to the protein, glycosylation sites, glycan variation, and glycan proportions at each site of the glycoprotein must be analyzed. Glycopeptide-based structural analysis technology using mass spectrometry has been developed; however, complicated analyses of complex spectra obtained by multistage fragmentation are necessary, and sensitivity and throughput of the analyses are low. Therefore, we developed a liquid chromatography/mass spectrometry (MS)-based glycopeptide analysis method to reveal the site-specific glycome (Glycan heterogeneity-based Relational IDentification of Glycopeptide signals on Elution profile, Glyco-RIDGE). This method used accurate masses and retention times of glycopeptides, without requiring MS2, and could be applied to complex mixtures. To increase the number of identified peptide, fractionation of sample glycopeptides for reduction of sample complexity is required. Therefore, in this study, glycopeptides were fractionated into four fractions by hydrophilic interaction chromatography, and each fraction was analyzed using the Glyco-RIDGE method. As a result, many glycopeptides having long glycans were enriched in the highest hydrophilic fraction. Based on the monosaccharide composition, these glycans were thought to be poly-N-acetyllactosamine (polylactosamine [pLN]), and 31 pLN-carrier proteins were identified in HL-60 cells. Gene ontology enrichment analysis revealed that pLN carriers included many molecules related to signal transduction, receptors, and cell adhesion. Thus, these findings provided important insights into the analysis of the glycoproteome using our novel Glyco-RIDGE method.ᅟ [ABSTRACT FROM AUTHOR]

β-1,3-N-Acetylglucosaminyltransferase 8 (β3GnT8) is a key enzyme that catalyzes the formation of polylactosamine glycan structures by transferring GlcNAc to tetra-antennary β1-6-branched N-glycans, and it has been reported to participate in tumor invasion and metastasis by regulating the expression of matrix metalloproteinases (MMPs), cluster of differentiation 147 (CD147) and polylactosamine. By contrast, the role of transcription factor c-Jun in cell cycle progression has been well established. c-Jun has an important role in tumor cell invasion and metastasis. However, the precise molecular mechanisms by which c-Jun regulates these processes in colorectal carcinoma cells are not fully elucidated. In the present study, c-Jun had a significant effect on the invasive and migratory abilities of SW480 and LoVo cells. Additionally, overexpression of c-Jun was able to increase the expression of β3GnT8, MMPs, CD147 and polylactosamine. Similarly, knockdown of c-Jun was able to decrease the expression of β3GnT8, MMPs, CD147 and polylactosamine. These results suggest that c-Jun is able to regulate colorectal carcinoma cell invasion and metastasis via β3GnT8. A chromatin immunoprecipitation assay indicated that c-Jun is able to bind directly to the promoter regions of β3GnT8 in SW480 and LoVo cells. This leads to transcriptional activation of β3GnT8, which in turn regulates the expression of tumor invasion and metastasis-associated genes. The results of the present study demonstrate a novel mechanism underlying colorectal carcinoma cell invasion and metastasis, where β3GnT8 is transcriptionally activated via c-Jun binding to its promoter. [ABSTRACT FROM AUTHOR]

Invertebrates lack canonical adaptive immunity and mainly rely on innate immune system to fight against pathogens. The phagocytes, which could engulf and kill microbial pathogens, are likely to be of great importance and have to undertake significant roles in invertebrate immune defense. In the present study, flow cytometry combined with histological and lectin staining was employed to characterise functional features of phagocytes in the Pacific oyster Crassostrea gigas. Based on the cell size and cellular contents, haemocytes were categorised into three cell types, i.e., granulocytes, semigranulocytes and agranulocytes. Agranulocytes with smaller cell volume and lower cytoplasmic-to-nuclear ratio did not show phagocytic activity, while semigranulocytes and agranulocytes exhibited larger cell volume, higher cytoplasmic-to-nuclear ratio and phagocytic activity. In addition, granulocytes with higher side scatter (SSC) exhibited higher phagocytic activity than that of semigranulocytes. When β-integrin and lectin-like receptors were blocked by RGD tripeptide and carbohydrates, respectively, the phagocytic activity of both granulocytes and semigranulocytes was significantly inhibited, indicating that β-integrin and certain lectin-like receptors were involved in phagocytosis towards microbes. Moreover, lipopolysaccharide but not peptidylglycan could enhance phagocytic activity of granulocytes and semigranulocytes towards Vibrio splendidus and Staphylococcus aureus. Lectin staining analysis revealed that Lycopersicon esculentum lectin (LEL), binding the epitope polylactosamine, was highly distributed on the extracellular cell surface of phagocytes, and could be utilized as a potential molecular marker to differentiate phagocytes from non-phagocytic haemocytes. The results, collectively, provide knowledge on the functional characters of oyster phagocytes, which would contribute to deep investigation of cell typing and cellular immunity in bivalves.

Abstract The cystic fibrosis transmembrane conductance regulator (CFTR) has been known for the past 11 years to be a membrane glycoprotein with chloride channel activity. Only recently has the glycosylation of CFTR been examined in detail, by O'Riordan et al in Glycobiology. Using cells that overexpress wild-type (wt)CFTR, the presence of polylactosamine was noted on the fully glycosylated form of CFTR. In the present commentary the results of that work are discussed in relation to the glycosylation phenotype of cystic fibrosis (CF), and the cellular localization and processing of ΔF508 CFTR. The significance of the glycosylation will be known when endogenous CFTR from primary human tissue is examined.

Alterations to N-linked glycans are closely associated with cancer progression. Of particular importance in tumor growth and invasion, is the synthesis of complex N-linked oligosaccharides containing poly-N-acetyllactosamine (polylactosamine) chains, which have previously been reported to inhibit 3'-azidothymidine (AZT). Cluster of differentiation 147 (CD147) is a glycoprotein that carries β1,6-branched polylactosamine sugars on its N-glycans. The present study aimed to explore the mechanism by which AZT may affect matrix metalloproteinase-2 (MMP2) expression and the cell cycle via regulation of the N-glycans on CD147 in SGC-7901 and U251 cell lines. Subsequent to treatment with various concentrations of AZT, the N-glycans of highly glycosylated (HG)-CD147 were observed to decrease in the two cell lines, and the expression of MMP2 was also significantly decreased. In addition, cell cycle analysis demonstrated that the percentage of the cells in the G1 phase increased in a dose-dependent manner with AZT treatment, indicating that AZT may inhibit cell proliferation in SGC-7901 cells. It was suggested that AZT may reduce the biosynthesis of polylactosamine chains on CD147 and reduce MMP2 expression to inhibit cell proliferation in SGC-7901 and U251 cells. Thus, AZT is suggested to be an antineoplastic drug, which may be effective therapeutically for certain types of cancer through acting on the N-glycans of HG-CD147. [ABSTRACT FROM AUTHOR]

5-Fluorouracil (5-FU) is the major chemotherapeutic agent for the treatment of colorectal carcinoma, which were found to have N-glycans containing polylactosamine on the cancer cell surface. Alterations in the expression and structure of polylactosamine glycans are associated with cellular differentiation and oncogenesis. However, little is known with regard to the correlation between the levels of polylactosamine expressed in colon cancer cells and the anticancer effect of 5-FU. In the present study, SW620 cells were treated with the half maximal inhibitory concentration (IC50; determined by MTT-assay) of 5-FU. Hoechst 33258 staining and flow cytometric analysis indicated that 5-FU administration resulted in apoptosis in SW620 cells. An increased percentage of cells in S phase was also observed among the SW620 cells treated with 5-FU. Under the same experimental conditions, a decrease in the 5-FU-induced inhibition of polylactosamine glycans was recorded. However, an increase in the activity of alkaline phosphatase was also observed. Furthermore, pretreatment of the SW620 cells with 5-FU inhibited the expression of β1,3-N-acetylglucosaminyltransferase-8 (β3Gn-T8) and cluster of differentiation (CD)147 in a time-dependent manner- Overall, changes in glycosylation were associated with the anticancer effect of 5-FU in the colon cancer cells. In conclusion, polylactosamine may be a useful target for the identification of substances with anticancer activity. [ABSTRACT FROM AUTHOR]

Linear polysaccharides are typically composed of repeating mono- or disaccharide units and are ubiquitous among living organisms. Polysaccharide diversity arises from chain-length variation, branching, and additional modifications. Structural diversity is associated with various physiological functions, which are often regulated by cognate polysaccharide-binding proteins. Proteins that interact with linear polysaccharides have been identified or developed, such as galectins and polysaccharide-specific antibodies, respectively. Currently, data is accumulating on the three-dimensional structure of polysaccharide-binding proteins. These proteins are classified into two types: exo-type and endo-type. The former group specifically interacts with the terminal units of polysaccharides, whereas the latter with internal units. In this review, we describe the structural aspects of exo-type and endo-type protein-polysaccharide interactions. Further, we discuss the structural basis for affinity and specificity enhancement in the face of inherently weak binding interactions. [ABSTRACT FROM AUTHOR]

The authors discuss the use of targeted next-generation sequencing to characterize colorectal cancer (CRC)-related mutational alterations in genes encoding glycosylation enzymes. Topics include various genes that showed mutational alterations in CRCs with 12 genes exhibiting higher mutation rates, the hypoglycosylation of Mucin-1 protein, and the migration of colon cancer cells.

In a previous study, we demonstrated that β1,3-N-acetylglucosaminyltransferase 5 (B3gnt5) is a lactotriaosylceramide (Lc3Cer) synthase that synthesizes a precursor structure for lacto/neolacto-series glycosphingolipids (GSL5) in in vitro experiments. Here, we generated B3gnt5-deficient (B3gnt5T-/-) mice to investigate the in vivo biological functions of lacto/neolacto-series GSLs. In biochemical analyses. lacto/neolacto-series GSLS were confirmed to be absent and no Lc3Cer synthase activity was detected in the tissues of these mice. These results demonstrate that β3GnT5 is the sole enzyme synthesizing Lc3Cer in vivo. Ganglioside GM1, known as a glycosphingolipid-enriched microdomain (GEM) marker, was found to be upregulated in B3gnt5T-/- B cells by flow cytometry and fluorescence microscopy. However, no difference in the amount of GM1 was observed by TLC-immunoblotting analysis. The GEM-stained puncta on the surface of B3gnt5-/- resting B cells were brighter and larger than those of WI cells. These results suggest that structural alteration of GEM occurs in B3gnt5-/- B cells. We next examined whether BCR signaling related proteins, such as BCR, CD19, and the signaling molecule Lyn, had moved into or out of the GEM fraction. In B3gnt5T-/- B cells, these molecules were enriched in the GEM fraction or adjacent fraction. Moreover, B3gnt5T-/- B cells were more sensitive to the induction of intracellular phosphorylation signals on BCR stimulation and proliferated more vigorously than WI B cells. Together, these results suggest that Iacto/neolacto-series GSLs play an important role in clustering of GEMs and tether-specific proteins, such as BCR, CD19, and related signaling molecules to the GEMs. [ABSTRACT FROM AUTHOR]

Abstract: At an early stage of apoptosis, Jurkat cells transiently become susceptible to binding and phagocytosis by macrophages through the polylactosamine-type carbohydrate chains of CD43 [J. Biol. Chem. 279 (2004) 5967]. Susceptibility of apoptotic Jurkat cells to macrophage recognition was studied over an extended time range of 0–24h including a later stage. Jurkat cells incubated with appropriate concentrations of apoptosis-inducing agents etoposide or anti-Fas antibody became susceptible to macrophage-binding at 2h, and the susceptibility fell to the control level at 4 or 6h. However, it increased again at later hours (6–24h). Flow cytometric analyses of CD43 and phosphatidylserine (PS) on the apoptotic cells indicated that CD43 began to degrade at around 4h, and PS is externalized significantly at 4 or 6h. The macrophage-binding at 2h was prevented by glycosidase treatment of Jurkat cells, but not by annexin V. Conversely, the later binding at 12 or 18h was not prevented by glycosidase treatment, but was done so by annexin V. These results suggest that Jurkat cells become susceptible to phagocytic removal at an early stage of apoptosis by the carbohydrate-mediated mechanism, and at a later stage by the PS-mediated mechanism. [Copyright &y& Elsevier]

Cell surface complex carbohydrates have emerged as key recognition molecules, mediating physiological interactions between cells. Typically, glycans on one cell surface are engaged by complementary carbohydrate binding proteins (lectins) on an apposing cell, initiating appropriate cellular responses. Although many cell surface lectins have been identified in vertebrates, only a few of their endogenous carbohydrate ligands have been established. Each major class of cell surface glycans—glycoproteins, glycolipids, and proteoglycans—has been implicated as physiologically relevant lectin ligands. The current minireview focuses on findings that implicate glycosphingolipids as especially important molecules in cell–cell recognition in two different systems: the recognition of human leukocytes by E-selectin on the vascular endothelium during inflammation and the recognition of nerve cell axons by myelin-associated glycoprotein in myelin–axon stabilization and the regulation of axon regeneration. [Copyright &y& Elsevier]

Although a large body of structural data exists for bronchial mucins from cystic fibrosis (CF) and chronic bronchitis (CB) patients, little is known about terminal structures carried on poly- N-acetyllactosamine antennae. Such structures are of interest because they are potential ligands for bacterial adhesins and other lectins. In this study, we have used fast atom bombardment mass spectrometry (FAB-MS) to examine terminal sequences released by endo-β-galactosidase from O-glycans obtained by reductive elimination of bronchial mucins purified from the sputum of 8 CF and 8 CB patients. Our data show that, although the polylactosamine antennae of CF and CB mucins have several terminal sequences in common, they differ significantly in their sialyl Lewisx (NeuAcα2-3Galβ1-4[Fucα1-3]GlcNAcβ1-) content. Thus all examined mucins from CF patients carry sialyl Lewisx on their polylactosamine antennae, whereas this type of epitope is present on only three out of the eight CB mucins examined, notably in the airways of one CB patient which were heavily infected by Pseudomonas aeruginosa as are the airways of all the CF patients. This suggests that, in airway mucins, the expression of sialyl Lewisx on polylactosamine antennae is probably more related to inflammation and infection than to a direct effect of the CF defect. [ABSTRACT FROM AUTHOR]

The cystic fibrosis transmembrane conductance regulator (CFTR) has been known for the past 11 years to be a membrane glycoprotein with chloride channel activity. Only recently has the glycosylation of CFTR been examined in detail, by O'Riordan et al in Glycobiology. Using cells that overexpress wild-type (wt)CFTR, the presence of polylactosamine was noted on the fully glycosylated form of CFTR. In the present commentary the results of that work are discussed in relation to the glycosylation phenotype of cystic fibrosis (CF), and the cellular localization and processing of ΔF508 CFTR. The significance of the glycosylation will be known when endogenous CFTR from primary human tissue is examined. [ABSTRACT FROM AUTHOR]

In this paper, the chemical synthesis of polylactosamine fragments up to docosasaccharide (22-mer) via the blockwise synthetic approach is reported. We used suitably protected tetrasaccharide and octasaccharide sequences as key building blocks. The use of such large building blocks as glycosyl donors and acceptors enabled the rapid construction of polysaccharide frameworks. Furthermore, the coupling reaction between these large building blocks facilitated the purification of glycosylated products, for which size exclusion column chromatography is highly effective. Then, we applied the building blocks to the synthesis of keratan sulfate glycan, which is partially sulfated poly- N -acetyllactosamine. Consequently, we achieved the synthesis of the octasaccharide of a keratan sulfate glycan comprised of a repeating Galβ(1 → 4)GlcNAc6Sβ disaccharide unit. [Display omitted] • Chemical synthesis of polylactosamine fragments up to docosasaccharide was achieved. • Keratan sulfate octasaccharide was chemically synthesized for the first time. • The blockwise synthetic strategy efficiently delivered polysaccharide frameworks. [ABSTRACT FROM AUTHOR]

The organ-specific nature of the glycosylation of Na+,K+-ATPase-enriched preparations from kidney and brain tissues has earlier been indicated by the use of lectin-staining techniques. Na+,K+-ATPase is ubiquitous and abundant, and subject to upregulation during cell-division and in certain pathological conditions. Lectins specific for the different carbohydrates displayed by the Na+,K+-ATPases may, therefore, be useful carriers/mediators in tissue-specific targeting. N-linked oligosaccharides purified from Na+,K+-ATPase-enriched preparations from rat brain and kidney were consequently characterised in detail in this study using weak anion exchange and normal phase HPLC (combined with serial glycosidase digestions) and matrix-assisted laser desorption/ionisation mass spectrometry. The oligomannose series of glycans were most abundant in the brain tissue preparation and this contrasted with the renal-associated oligosaccharides that were dominated by families of tetra-antennary glycans (with/without a core fucose) with up to four lactosaminylglycan residues in either branched or linear formation. [ABSTRACT FROM AUTHOR]

Glycosylated [Asn22]lysozyme has been shown to contain N-acctyllactosamine repeats when expressed in chinese hamster ovary (CHO) cells. We find that the major portion of N-acetyllactosamine repeats are associated with diantennary oligosaccharides, In Lec2 CHO cells, which arc deficient in sialylation, glycosylated lysozyme is synthesized with increased contents of N-acetyllactosamine repeats terminating in β-galactosyl residues, In the Lec2 cells and the parental CHO cell line, Pro-5, only a minor portion of the oligosaccharides in lysozyme are of the triantennary type. Previously, it has been shown that the synthesis of N-acetyllactosamine repeats in Asn-linked oligosaccharides is enhanced by an increase in the activity of the elongating β-N-acetylglucosaminyl transferase and by the synthesis of β-1, 6-1inked antennae. The results with glycosylated lysozyme suggest that glycoproteins bearing diantennary oligosaccharides can contain several N-acetyllactosamine repeats and that the number of the latter can be increased by decreasing the activity of the capping sialyl transferases. [ABSTRACT FROM AUTHOR]

A HEMPAS (hereditary erythroblastic multinuclearity with positive acidified serum test) erythrocyte, atypical Variant II (referred to herein as Variant II-gal), lacking long-chain polylactosamine on both glycoproteins (Band 3 and 4.5) and glycosphingolipids, was characterized by the carbohydrate profile of the erythrocyte membrane according to Fukuda . (, 73, 1331–1339, 1989). Two laboratories previously reported that polylactosamine isolated from the erythrocyte protein Band 3 inhibited invasion of red blood cells by in malarial culture, suggesting a role for this carbohydrate in adhesion of the parasite. Therefore, HEMPAS erythrocyte Variant II-gal presented a unique opportunity to further examine this premise. Freshly drawn blood samples (normal and HEMPAS Variant II-gal) were separately incubated with from mannitol-synchronized cultures. The parasite was found to invade HEMPAS Variant II-gal erythrocytes at a 30% lower rate through two life cycles, as shown by microscopic evaluation of invasion and by [H]hypoxanthine incorporation into parasite. This observation, along with the published fact that glycophorin-deficient MM cells are also infectable, but at a lower rate, indicates that neither sialoglycoproteins nor polylactosamines are an obligate adhesive ligand for , although the possibility remains that either may still contribute to adhesive events during infection. [ABSTRACT FROM PUBLISHER]

Purpose: Using a recently developed matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) method, human breast cancer formalin-fixed paraffin-embedded (FFPE) tissue sections and tissue microarrays (TMA) are evaluated for N-linked glycan distribution in the tumor microenvironment., Experimental Design: Tissue sections representing multiple human epidermal growth factor receptor 2 (HER2) receptor-positive and triple-negative breast cancers (TNBC) in both TMA and FFPE slide format are processed for high resolution N-glycan MALDI-IMS. An additional FFPE tissue cohort of primary and metastatic breast tumors from the same donors are also evaluated., Results: The cumulative N-glycan MALDI-IMS analysis of breast cancer FFPE tissues and TMAs indicate the distribution of specific glycan structural classes to stromal, necrotic, and tumor regions. A series of high-mannose, branched and fucosylated glycans are detected predominantly within tumor regions. Additionally, a series of polylactosamine glycans are detected in advanced HER2+, TNBC, and metastatic breast cancer tissues. Comparison of tumor N-glycan species detected in paired primary and metastatic tissues indicate minimal changes between the two conditions., Conclusions and Clinical Relevance: The prevalence of tumor-associated polylactosamine glycans in primary and metastatic breast cancer tissues indicates new mechanistic insights into the development and progression of breast cancers. The presence of these glycans could be targeted for therapeutic strategies and further evaluation as potential prognostic biomarkers., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)