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Biomolecules Jan 2022The brain N-glycome is known to be crucial for many biological functions, including its involvement in neuronal diseases. Although large structural studies of brain...
The brain N-glycome is known to be crucial for many biological functions, including its involvement in neuronal diseases. Although large structural studies of brain N-glycans were recently carried out, a comprehensive isomer-specific structural analysis has still not been achieved, as indicated by the recent discovery of novel structures with galactosylated bisecting GlcNAc. Here, we present a detailed, isomer-specific analysis of the human brain N-glycome based on standardized porous graphitic carbon (PGC)-LC-MS/MS. To achieve this goal, we biosynthesized glycans with substitutions typically occurring in the brain N-glycome and acquired their normalized retention times. Comparison of these values with the standardized retention times of neutral and desialylated N-glycan fractions of the human brain led to unambiguous isomer specific assignment of most major peaks. Profound differences in the glycan structures between naturally neutral and desialylated glycans were found. The neutral and sialylated N-glycans derive from diverging biosynthetic pathways and are biosynthetically finished end products, rather than just partially processed intermediates. The focus on structural glycomics defined the structure of human brain N-glycans, amongst these are HNK-1 containing glycans, a bisecting sialyl-lactose and structures with fucose and -acetylgalactosamine on the same arm, the so-called LDNF epitope often associated with parasitic worms.
Topics: Acetylgalactosamine; Brain; Brain Chemistry; Chromatography, Liquid; Fucose; Glycomics; Graphite; Humans; Lactose; Sialic Acids; Tandem Mass Spectrometry
PubMed: 35053234
DOI: 10.3390/biom12010085 -
Blood Jan 2019Regular prophylaxis with factor VIII (FVIII) or FIX products to prevent bleeding in patients with severe hemophilia A (HA) and HB, respectively, results in marked... (Review)
Review
Regular prophylaxis with factor VIII (FVIII) or FIX products to prevent bleeding in patients with severe hemophilia A (HA) and HB, respectively, results in marked suppression of the onset of arthropathy and contributes greatly to improvements in quality of life. Some issues remain with the use of clotting factor replacement therapy, however. The need for multiple IV infusions is associated with a substantial mental and physical burden, and the hemostatic effect of bypassing agents (BPAs) in patients with inhibitor is inconsistent. The development of subcutaneous products with prolonged hemostatic efficiency, irrespective of the presence of inhibitors, has been a longtime wish for patients. A new class of therapeutic agents that act by enhancing coagulation (emicizumab) and inhibiting anticoagulant pathways (fitusiran and concizumab) have been established, and clinical trials using these nonfactor products are ongoing. The current findings have demonstrated that prophylaxis by nonfactor products supports marked reductions of bleeding episodes in hemophilia patients with or without inhibitor. Emicizumab has already been approved for use internationally. Some concerns are evident, however. Thrombotic microangiopathy and thromboembolism have occurred in 5 emicizumab-treated patients receiving repeated infusions of activated prothrombin complex concentrates, and a sinus vein thrombosis has occurred in a fitusiran-treated patient receiving repeated infusions of FVIII product. Moreover, reliable techniques to monitor hemostatic function in patients receiving nonfactor products with concomitant BPA or FVIII/FIX therapies require further assessment. These novel therapeutic agents have promising hemostatic properties, although wider experience in hemophilia centers is warranted to establish appropriate therapeutic strategies.
Topics: Acetylgalactosamine; Animals; Antibodies, Bispecific; Antibodies, Monoclonal, Humanized; Blood Coagulation; Coagulants; Hemophilia A; Hemophilia B; Hemostasis; Humans; RNA, Small Interfering; Thromboembolism
PubMed: 30559263
DOI: 10.1182/blood-2018-07-820712 -
Annals of Anatomy = Anatomischer... Oct 2022Urothelium is a multilayer epithelium covering the inner surface of the urinary bladder that acts as a blood-urine barrier and is involved in maintaining the wellbeing...
BACKGROUND
Urothelium is a multilayer epithelium covering the inner surface of the urinary bladder that acts as a blood-urine barrier and is involved in maintaining the wellbeing of the whole organism. Glycans serve in the maturation and differentiation of cells and thus play a key role in the morphology and function of the multilayered epithelium. The aim of the present study was to examine the glycoprotein pattern of the horse urinary bladder urothelium by lectin histochemistry.
METHODS
The study involved urinary bladders from four horse stallions. Tissue sections were stained with a panel of eleven lectins, in combination with saponification and sialidase digestion (Ks).
RESULTS
Basal cells displayed high-mannose N-glycans (Con A), α2,6-linked sialic acid (SNA), and O-linked sialoglycans with sialic acids linked to Galβl,3GalNAc (T antigen) (KsPNA) and terminal N-acetylgalactosamine (Tn antigen) (KsSBA). The young intermediate cells expressed terminal N-acetylglucosamine (GlcNAc) (GSA II), galactose (GSA I-B), T- and Tn antigens (PNA, SBA). The mature intermediate cells showed additional high-mannose N-glycans, O-linked sialoglycans (sialyl-T antigen, sialyl-Tn antigen), α2,6- and α2,3-linked sialic acid (MAL II), α1,2-linked fucose (UEA I), and GlcNAc (KsWGA). The latter residue marked the boundary with the overlying surface layer. Few Con A positive intermediate cells were seen to cross the entire urothelium thickness. The surface cells showed additional glycans such as T antigen and sialic acids linked to GalNAc binding DBA (KsDBA). Few surface cells contained α1,3-linked fucose (LTA), whereas some other cells displayed intraluminal secretion of mucin-type glycans terminating with GalNAcα1,3(LFucα1,2)Galβ1,3/4GlcNAcβ1 (DBA). The luminal surface expressed the most complex glycan pattern in the urothelium because only α1,3-linked fucose lacked among the demonstrated glycans.
CONCLUSIONS
This study showed that the glycan pattern becomes more complex from the basal to surface layer of the urothelium and that surface cells could modify the composition of urine via the secretion of glycoproteins.
Topics: Horses; Male; Animals; Urothelium; Urinary Bladder; Mannose; N-Acetylneuraminic Acid; Neuraminidase; Fucose; Galactose; Acetylgalactosamine; Acetylglucosamine; Polysaccharides; Lectins; Glycoproteins; Mucins; Antigens, Viral, Tumor
PubMed: 35987426
DOI: 10.1016/j.aanat.2022.151988 -
The Journal of Physical Chemistry. A Oct 2022In the present work, we report the first rotational study of -acetylgalactosamine, a cancer-associated sugar derivative, by means of high-resolution rotational...
In the present work, we report the first rotational study of -acetylgalactosamine, a cancer-associated sugar derivative, by means of high-resolution rotational spectroscopy. Two different conformers have been conclusively characterized using broadband Fourier transform microwave spectroscopy coupled with a laser ablation vaporization system. Additionally, we performed a comprehensive analysis of the intramolecular interactions that govern these structures, which allowed us to both characterize the existence of intramolecular hydrogen bond networks that drive the intrinsic conformation panorama of -acetylgalactosamine and further rationalize the biological role of this aminosugar derivative as part of the Tn antigen.
Topics: Humans; Acetylgalactosamine; Molecular Conformation; Hydrogen Bonding; Organic Chemicals; Neoplasms; Sugars
PubMed: 36099577
DOI: 10.1021/acs.jpca.2c04595 -
Applied Microbiology and Biotechnology Jan 2017Lacto-N-biose (LNB) and galacto-N-biose (GNB) are major building blocks of free oligosaccharides and glycan moieties of glyco-complexes present in human milk and...
Lacto-N-biose (LNB) and galacto-N-biose (GNB) are major building blocks of free oligosaccharides and glycan moieties of glyco-complexes present in human milk and gastrointestinal mucosa. We have previously characterized the phospho-β-galactosidase GnbG from Lactobacillus casei BL23 that is involved in the metabolism of LNB and GNB. GnbG has been used here in transglycosylation reactions, and it showed the production of LNB and GNB with N-acetylglucosamine and N-acetylgalactosamine as acceptors, respectively. The reaction kinetics demonstrated that GnbG can convert 69 ± 4 and 71 ± 1 % of o-nitrophenyl-β-D-galactopyranoside into LNB and GNB, respectively. Those reactions were performed in a semi-preparative scale, and the synthesized disaccharides were purified. The maximum yield obtained for LNB was 10.7 ± 0.2 g/l and for GNB was 10.8 ± 0.3 g/l. NMR spectroscopy confirmed the molecular structures of both carbohydrates and the absence of reaction byproducts, which also supports that GnbG is specific for β1,3-glycosidic linkages. The purified sugars were subsequently tested for their potential prebiotic properties using Lactobacillus species. The results showed that LNB and GNB were fermented by the tested strains of L. casei, Lactobacillus rhamnosus (except L. rhamnosus strain ATCC 53103), Lactobacillus zeae, Lactobacillus gasseri, and Lactobacillus johnsonii. DNA hybridization experiments suggested that the metabolism of those disaccharides in 9 out of 10 L. casei strains, all L. rhamnosus strains and all L. zeae strains tested relies upon a phospho-β-galactosidase homologous to GnbG. The results presented here support the putative role of human milk oligosaccharides for selective enrichment of beneficial intestinal microbiota in breast-fed infants.
Topics: Acetylgalactosamine; Acetylglucosamine; Disaccharides; Glycoside Hydrolases; Glycosylation; Intestinal Mucosa; Kinetics; Lactobacillus; Magnetic Resonance Spectroscopy; Milk, Human; Nucleic Acid Hybridization; Prebiotics
PubMed: 27714445
DOI: 10.1007/s00253-016-7882-0 -
Molecular Therapy : the Journal of the... Mar 2024N-Acetylgalactosamine (GalNAc)-conjugated small interfering RNA (siRNA) therapies have received approval for treating both orphan and prevalent diseases. To improve...
N-Acetylgalactosamine (GalNAc)-conjugated small interfering RNA (siRNA) therapies have received approval for treating both orphan and prevalent diseases. To improve in vivo efficacy and streamline the chemical synthesis process for efficient and cost-effective manufacturing, we conducted this study to identify better designs of GalNAc-siRNA conjugates for therapeutic development. Here, we present data on redesigned GalNAc-based ligands conjugated with siRNAs against angiopoietin-like 3 (ANGPTL3) and lipoprotein (a) (Lp(a)), two target molecules with the potential to address large unmet medical needs in atherosclerotic cardiovascular diseases. By attaching a novel pyran-derived scaffold to serial monovalent GalNAc units before solid-phase oligonucleotide synthesis, we achieved increased GalNAc-siRNA production efficiency with fewer synthesis steps compared to the standard triantennary GalNAc construct L96. The improved GalNAc-siRNA conjugates demonstrated equivalent or superior in vivo efficacy compared to triantennary GalNAc-conjugated siRNAs.
Topics: Humans; RNA, Small Interfering; Hepatocytes; Cardiovascular Diseases; Cost-Benefit Analysis; RNA, Double-Stranded; Acetylgalactosamine; Angiopoietin-Like Protein 3
PubMed: 38204163
DOI: 10.1016/j.ymthe.2024.01.008 -
Expert Opinion on Therapeutic Patents 2023SiRNA molecules with a feature of good gene-silencing are critical for drug discovery and development based on RNA interference. GalNAc-RNA therapeutics is a rapid...
INTRODUCTION
SiRNA molecules with a feature of good gene-silencing are critical for drug discovery and development based on RNA interference. GalNAc-RNA therapeutics is a rapid growing area in RNA therapeutics.
AREAS COVERED
This article provides patent landscape and modification feature of GalNAc-RNA therapeutics. The US-granted patents from January 2004 to April 2023 were retrieved and analyzed.
EXPERT OPINION
Globally, our study is the first one to holistically depict a map of modifications and therapeutic applications for GalNAc-RNA therapeutics by patent data analysis. The results showed there were 8 major modifications and 5 new emerged modifications for GalNAc-RNA therapeutic agents. Especially, the study provides recent new emerged modifications in sugar, base, and internucleotide linkage of GalNAc-RNA therapeutic agents, e.g. morpholino-type ring, 5-methylcytosine, and phosphorodithioates. In addition, our study systematically demonstrated major therapeutic applications for GalNAc-RNA therapeutics, including liver or gallbladder disorders, anticancer, antihyperlipidemics, and disorders of the nervous system etc.
Topics: Humans; Acetylgalactosamine; Patents as Topic; Liver; RNA, Small Interfering; Gene Silencing; RNA Interference
PubMed: 37897177
DOI: 10.1080/13543776.2023.2277249 -
Angewandte Chemie (International Ed. in... Dec 2021Accessing large numbers of structurally diverse glycans and derivatives is essential to functional glycomics. We showed a general tolerance of galactosyltransferases...
Accessing large numbers of structurally diverse glycans and derivatives is essential to functional glycomics. We showed a general tolerance of galactosyltransferases toward uridine-diphosphate-galactosamine (UDP-GalN), which is not a commonly used sugar nucleotide donor. The property was harnessed to develop a two-step chemoenzymatic strategy for facile synthesis of novel and divergent N-acetylgalactosamine (GalNAc)-glycosides and derivatives in preparative scales. The discovery and the application of the new property of existing glycosyltransferases expand their catalytic capabilities in generating novel carbohydrate linkages, thus prompting the synthesis of diverse glycans and glycoconjugates for biological studies.
Topics: Carbohydrate Conformation; Galactosyltransferases; Helicobacter pylori; Neisseria meningitidis; Uridine Diphosphate N-Acetylgalactosamine
PubMed: 34661966
DOI: 10.1002/anie.202112574 -
Journal of the American Chemical Society Aug 2019O-Linked α--acetylgalactosamine (O-GalNAc) glycans constitute a major part of the human glycome. They are difficult to study because of the complex interplay of 20...
O-Linked α--acetylgalactosamine (O-GalNAc) glycans constitute a major part of the human glycome. They are difficult to study because of the complex interplay of 20 distinct glycosyltransferase isoenzymes that initiate this form of glycosylation, the polypeptide -acetylgalactosaminyltransferases (GalNAc-Ts). Despite proven disease relevance, correlating the activity of individual GalNAc-Ts with biological function remains challenging due to a lack of tools to probe their substrate specificity in a complex biological environment. Here, we develop a "bump-hole" chemical reporter system for studying GalNAc-T activity in vitro. Individual GalNAc-Ts were rationally engineered to contain an enlarged active site (hole) and probed with a newly synthesized collection of 20 (bumped) uridine diphosphate -acetylgalactosamine (UDP-GalNAc) analogs to identify enzymesubstrate pairs that retain peptide specificities but are otherwise completely orthogonal to native enzymesubstrate pairs. The approach was applicable to multiple GalNAc-T isoenzymes, including GalNAc-T1 and -T2 that prefer nonglycosylated peptide substrates and GalNAcT-10 that prefers a preglycosylated peptide substrate. A detailed investigation of enzyme kinetics and specificities revealed the robustness of the approach to faithfully report on GalNAc-T activity and paves the way for studying substrate specificities in living systems.
Topics: Acetylgalactosamine; Amino Acid Sequence; Catalytic Domain; Humans; Isoenzymes; Kinetics; Models, Molecular; Mutagenesis; N-Acetylgalactosaminyltransferases; Protein Engineering; Substrate Specificity; Uridine Diphosphate; Polypeptide N-acetylgalactosaminyltransferase
PubMed: 31373799
DOI: 10.1021/jacs.9b04695 -
The New England Journal of Medicine Nov 2020
Topics: Acetylgalactosamine; Amides; Humans; Porphyria, Acute Intermittent; Pyrrolidines
PubMed: 33176092
DOI: 10.1056/NEJMc2026458