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Glycobiology Oct 2022N-glycolylated carbohydrates are amino sugars with an N-glycolyl amide group. These glycans have not been well studied due to their surprising rarity in nature in... (Review)
Review
N-glycolylated carbohydrates are amino sugars with an N-glycolyl amide group. These glycans have not been well studied due to their surprising rarity in nature in comparison with N-acetylated carbohydrates. Recently, however, there has been increasing interest in N-glycolylated sugars because the non-human sialic acid N-glycolylneuraminic acid (Neu5Gc), apparently the only source of all N-glycolylated sugars in deuterostomes, appears to be involved in xenosialitis (inflammation associated with consumption of Neu5Gc-rich red meats). Xenosialitis has been implicated in cancers as well as other diseases including atherosclerosis. Furthermore, metabolites of Neu5Gc have been shown to be incorporated into glycosaminoglycans (GAGs), resulting in N-glycolylated GAGs. These N-glycolylated GAGs have important potential applications, such as dating the loss of the Neu5Gc-generating CMAH gene in humans and being explored as a xenosialitis biomarker and/or estimate of the body burden of diet-derived Neu5Gc, to understand the risks associated with the consumption of red meats. This review explores N-glycolylated carbohydrates, how they are metabolized to N-glycolylglucosamine and N-glycolylgalactosamine, and how these metabolites can be incorporated into N-glycolylated GAGs in human tissues. We also discuss other sources of N-glycolylated sugars, such as recombinant production from microorganisms using metabolic engineering as well as chemical synthesis.
Topics: Humans; Neuraminic Acids; N-Acetylneuraminic Acid; Amino Sugars; Polysaccharides; Inflammation
PubMed: 35925816
DOI: 10.1093/glycob/cwac048 -
Nature Sep 2022Bacterial cell wall components provide various unique molecular structures that are detected by pattern recognition receptors (PRRs) of the innate immune system as...
Bacterial cell wall components provide various unique molecular structures that are detected by pattern recognition receptors (PRRs) of the innate immune system as non-self. Most bacterial species form a cell wall that consists of peptidoglycan (PGN), a polymeric structure comprising alternating amino sugars that form strands cross-linked by short peptides. Muramyl dipeptide (MDP) has been well documented as a minimal immunogenic component of peptidoglycan. MDP is sensed by the cytosolic nucleotide-binding oligomerization domain-containing protein 2 (NOD2). Upon engagement, it triggers pro-inflammatory gene expression, and this functionality is of critical importance in maintaining a healthy intestinal barrier function. Here, using a forward genetic screen to identify factors required for MDP detection, we identified N-acetylglucosamine kinase (NAGK) as being essential for the immunostimulatory activity of MDP. NAGK is broadly expressed in immune cells and has previously been described to contribute to the hexosamine biosynthetic salvage pathway. Mechanistically, NAGK functions upstream of NOD2 by directly phosphorylating the N-acetylmuramic acid moiety of MDP at the hydroxyl group of its C6 position, yielding 6-O-phospho-MDP. NAGK-phosphorylated MDP-but not unmodified MDP-constitutes an agonist for NOD2. Macrophages from mice deficient in NAGK are completely deficient in MDP sensing. These results reveal a link between amino sugar metabolism and innate immunity to bacterial cell walls.
Topics: Acetylmuramyl-Alanyl-Isoglutamine; Animals; Bacteria; Cell Wall; Hexosamines; Immunity, Innate; Macrophages; Mice; Nod2 Signaling Adaptor Protein; Peptidoglycan; Phosphorylation; Phosphotransferases (Alcohol Group Acceptor)
PubMed: 36002575
DOI: 10.1038/s41586-022-05125-x -
BioTechniques Feb 2021Five established clearing protocols were compared with a modified and simplified method to determine an optimal clearing reagent for three-dimensionally visualizing...
Five established clearing protocols were compared with a modified and simplified method to determine an optimal clearing reagent for three-dimensionally visualizing fluorophores in the murine liver, a challenging organ to clear. We report successful clearing of whole liver lobes by modification of an established protocol (UbasM) using only Ub-1, a urea-based amino sugar reagent, in a simpler protocol that requires only a 24-h processing time. With Ub-1 alone, we observed sufficiently preserved liver tissue structure in three dimensions along with excellent preservation of fluorophore emissions from endogenous protein reporters and lipophilic tracer dyes. This streamlined technique can be used for 3D cell lineage tracing and fluoroprobe-based reporter gene expression to compare various experimental conditions.
Topics: Amino Sugars; Animals; Fluorescence; Fluorescent Dyes; Liver; Mice; Urea
PubMed: 33467918
DOI: 10.2144/btn-2020-0063 -
Molecules (Basel, Switzerland) Mar 2018Nucleic acids and carbohydrates are essential biomolecules involved in numerous biological and pathological processes. Development of multifunctional building blocks... (Review)
Review
Nucleic acids and carbohydrates are essential biomolecules involved in numerous biological and pathological processes. Development of multifunctional building blocks based on nucleosides and sugars is in high demand for the generation of novel oligonucleotide mimics and glycoconjugates for biomedical applications. Recently, aminooxyl-functionalized compounds have attracted increasing research interest because of their easy derivatization through oxime ligation or -oxyamide formation reactions. Various biological applications have been reported for -amino carbohydrate- and nucleoside-derived compounds. Here, we report our efforts in the design and synthesis of glyco-, glycosyl, nucleoside- and nucleo-aminooxy acid derivatives from readily available sugars and amino acids, and their use for the generation of -oxyamide-linked oligosaccharides, glycopeptides, glycolipids, oligonucleosides and nucleopeptides as novel glycoconjugates or oligonucleotide mimics. Delicate and key points in the synthesis will be emphasized.
Topics: Amino Sugars; Molecular Structure; Nucleosides; Oximes
PubMed: 29534554
DOI: 10.3390/molecules23030641 -
BMC Biology Jul 2019Altered metabolism and deregulated cellular energetics are now considered a hallmark of all cancers. Glucose, glutamine, fatty acids, and amino acids are the primary... (Review)
Review
Altered metabolism and deregulated cellular energetics are now considered a hallmark of all cancers. Glucose, glutamine, fatty acids, and amino acids are the primary drivers of tumor growth and act as substrates for the hexosamine biosynthetic pathway (HBP). The HBP culminates in the production of an amino sugar uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) that, along with other charged nucleotide sugars, serves as the basis for biosynthesis of glycoproteins and other glycoconjugates. These nutrient-driven post-translational modifications are highly altered in cancer and regulate protein functions in various cancer-associated processes. In this review, we discuss recent progress in understanding the mechanistic relationship between the HBP and cancer.
Topics: Biosynthetic Pathways; Hexosamines; Neoplasms; Protein Processing, Post-Translational; Proteins
PubMed: 31272438
DOI: 10.1186/s12915-019-0671-3 -
PloS One 2012Streptococcus mutans is a cariogenic pathogen that produces an extracellular polysaccharide (glucan) from dietary sugars, which allows it to establish a reproductive...
Streptococcus mutans is a cariogenic pathogen that produces an extracellular polysaccharide (glucan) from dietary sugars, which allows it to establish a reproductive niche and secrete acids that degrade tooth enamel. While two enzymes (GlmS and NagB) are known to be key factors affecting the entrance of amino sugars into glycolysis and cell wall synthesis in several other bacteria, their roles in S. mutans remain unclear. Therefore, we investigated the roles of GlmS and NagB in S. mutans sugar metabolism and determined whether they have an effect on virulence. NagB expression increased in the presence of GlcNAc while GlmS expression decreased, suggesting that the regulation of these enzymes, which functionally oppose one another, is dependent on the concentration of environmental GlcNAc. A glmS-inactivated mutant could not grow in the absence of GlcNAc, while nagB-inactivated mutant growth was decreased in the presence of GlcNAc. Also, nagB inactivation was found to decrease the expression of virulence factors, including cell-surface protein antigen and glucosyltransferase, and to decrease biofilm formation and saliva-induced S. mutans aggregation, while glmS inactivation had the opposite effects on virulence factor expression and bacterial aggregation. Our results suggest that GlmS and NagB function in sugar metabolism in opposing directions, increasing and decreasing S. mutans virulence, respectively.
Topics: Aldose-Ketose Isomerases; Amino Sugars; Biofilms; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Gene Knockout Techniques; Genes, Bacterial; Genetic Complementation Test; Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing); Humans; Models, Biological; Mutation; Streptococcus mutans; Virulence; Virulence Factors
PubMed: 22438919
DOI: 10.1371/journal.pone.0033382 -
The Journal of Biological Chemistry 2021The elongated antennae decorating eukaryotic glycans are built from polylactosamine repeats. Polylactosamine forms a lectin recognition site and also acts as a platform...
The elongated antennae decorating eukaryotic glycans are built from polylactosamine repeats. Polylactosamine forms a lectin recognition site and also acts as a platform for presenting diverse additional modifications (e.g., terminal cell-surface antigens); it therefore plays important roles in cell adherence, development, and immunity. Two new papers present a detailed structural and mechanistic investigation of β1-3-N-acetylgucosaminyltransferase 2, a key enzyme in antennae synthesis. The resulting insights will also help decipher other members of GT31, the single largest human glycosyltransferase family.
Topics: Amino Sugars; Glycosylation; N-Acetylglucosaminyltransferases; Polysaccharides
PubMed: 33453284
DOI: 10.1016/j.jbc.2020.100212 -
Frontiers in Immunology 2019The human mononuclear phagocytes system consists of dendritic cells (DCs), monocytes, and macrophages having different functions in bridging innate and adaptive... (Review)
Review
The human mononuclear phagocytes system consists of dendritic cells (DCs), monocytes, and macrophages having different functions in bridging innate and adaptive immunity. Among the heterogeneous population of monocytes the cell surface marker slan (6-sulfo LacNAc) identifies a specific subset of human CD14 CD16 non-classical monocytes, called slan monocytes (slanMo). In this review we discuss the identity and functions of slanMo, their contributions to immune surveillance by pro-inflammatory cytokine production, and cross talk with T cells and NK cells. We also consider the role of slanMo in the regulation of chronic inflammatory diseases and cancer. Finally, we highlight unresolved questions that should be the focus of future research.
Topics: Amino Sugars; Humans; Monocytes
PubMed: 31191513
DOI: 10.3389/fimmu.2019.00948 -
Journal of Pharmaceutical and... Feb 2020Erythropoiesis stimulating agents (ESAs) are a group of therapeutic glycoproteins used to treat anaemia caused by chronic kidney disease or chemotherapy. A variety of...
Erythropoiesis stimulating agents (ESAs) are a group of therapeutic glycoproteins used to treat anaemia caused by chronic kidney disease or chemotherapy. A variety of ESA products are available in the European Union, including innovator, biosimilar and second-generation medicines. Glycosylation is a critical quality attribute of ESA products, as it has a crucial influence upon in vivo biological activity. In this study, a combination of chromatography and mass spectrometry analysis has been used to characterise and compare the glycosylation profiles of five ESA products; Eprex® (epoetin alfa), NeoRecormon® (epoetin beta), Binocrit® (epoetin alfa biosimilar), Silapo (epoetin alfa biosimilar) and Aranesp® (darbepoetin alfa). The methods utilised include mixed-mode anion-exchange/hydrophilic interaction chromatography (AEX/HILIC-MS) for N-glycan identification and quantitation, and HILIC-MS for O-glycan characterisation. The products exhibit notable differences in N- and O-glycosylation, including attributes such as sialic acid occupation, O-acetylation, N-acetyllactosamine extended antennae and sulphated/penta-sialylated N-glycans, which have the potential to cause divergence of therapeutic potencies. The study highlights the need for continued monitoring of ESA product glycosylation, ideally allied to pharmacological data, in order to ensure consistency and therapeutic equivalence between products and enhance our understanding of ESA structure-activity-relationships.
Topics: Acetylation; Amino Sugars; Biosensing Techniques; Chromatography, High Pressure Liquid; Darbepoetin alfa; Epoetin Alfa; Erythropoietin; Glycosylation; Hematinics; Molecular Structure; N-Acetylneuraminic Acid; Polysaccharides; Recombinant Proteins; Tandem Mass Spectrometry
PubMed: 31838284
DOI: 10.1016/j.jpba.2019.113031 -
Molecules (Basel, Switzerland) Jun 2023Amino sugars are a kind of carbohydrates with one or more hydroxyl groups replaced by an amino group. They play crucial roles in a broad range of biological activities.... (Review)
Review
Amino sugars are a kind of carbohydrates with one or more hydroxyl groups replaced by an amino group. They play crucial roles in a broad range of biological activities. Over the past few decades, there have been continuing efforts on the stereoselective glycosylation of amino sugars. However, the introduction of glycoside bearing basic nitrogen is challenging using conventional Lewis acid-promoted pathways owing to competitive coordination of the amine to the Lewis acid promoter. Additionally, diastereomeric mixtures of -glycoside are often produced if aminoglycoside lack a C2 substituent. This review focuses on the updated overview of the way to stereoselective synthesis of 1,2--aminoglycoside. The scope, mechanism, and the applications in the synthesis of complex glycoconjugates for the representative methodologies were also included.
Topics: Amino Sugars; Lewis Acids; Carbohydrates; Glycoconjugates; Aminoglycosides; Cardiac Glycosides; Stereoisomerism
PubMed: 37375279
DOI: 10.3390/molecules28124724