Publications by authors named "Kiyohiko Angata"

Article Synopsis
  • The study focuses on the importance of measuring hepatitis B surface antigen (HBsAg) for the management of chronic hepatitis B virus infection (CHB) and examines preS1 protein expression in patients.
  • Researchers used seven monoclonal antibodies to analyze preS1 from various hepatitis B genotypes, discovering that the epitopes crucial for recognition are largely located in the aa33-47 region.
  • Findings indicate that preS1 expression remains stable across different HBsAg levels and genotypes, emphasizing its potential as a therapeutic target in treating CHB.
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  • The Human Glycome Atlas (HGA) Project, initiated in April 2023 by three Japanese institutions, aims to create a comprehensive knowledgebase of human glycans and glycoproteins.
  • This project is significant as it marks the first life sciences initiative supported by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) under a Large-scale Academic Frontiers Promotion Project.
  • Over its ten-year span, the HGA plans to analyze 20,000 blood samples and establish a resource (TOHSA) that will integrate glycan data with other omics and disease-related information.
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  • Glioma stem cells (GICs) are crucial for the resistance and recurrence of malignant gliomas, and this study investigates their maintenance and differentiation through an integrated proteogenomic approach.
  • Researchers found that chondroitin sulfate proteoglycan 4 (CSPG4) and its related enzymes are significantly involved in GIC functionality, with a focus on how their interaction and modification affect GIC behavior.
  • The results suggest that the carbohydrate modification on CSPG4 (termed CS-CSPG4) plays an essential role in nurturing GICs and may serve as a novel therapeutic target for treating glioblastoma.
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Glycosylation is increasingly recognized as a potential therapeutic target in Alzheimer's disease. In recent years, evidence of Alzheimer's disease-specific glycoproteins has been established. However, the mechanisms underlying their dysregulation, including tissue- and cell-type specificity, are not fully understood.

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Background: Serum hepatitis B surface antigen (HBsAg) is a component of both hepatitis B virus (HBV) virions and non-infectious subviral particles (SVPs). Recently, O-glycosylation of the PreS2 domain of middle HBsAg protein has been identified as a distinct characteristic of genotype C HBV virions versus SVPs. This study aimed to evaluate serum O-glycosylated HBsAg levels in patients with chronic hepatitis B (CHB) treated with nucleos(t)ide analogs (NAs).

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Background: Hepatitis B virus (HBV), which causes hepatitis, liver cirrhosis, and hepatocellular carcinoma, is a global human health problem. HBV contains three envelope proteins, S-, M-, and L-hepatitis B surface antigen (HBsAg). We recently found that O-glycosylated M-HBsAg, reactive with jacalin lectin, is one of the primary components of HBV DNA-containing virus particles.

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Cholangiocarcinoma (CCA) is a highly aggressive and metastatic type of malignant carcinoma that is associated with high mortality rates and is difficult to detect at early stages. Core 3 structure is a mucin-type -glycans synthesized by β1,3--acetylglucosaminyltransferase 6 (core 3 synthase), which plays an important role in the digestive system, in particular gastrointestinal goblet cells. It has been reported that core 3 synthase-expressing cells show lower migratory and invasive rates, and lower metastatic activity.

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Laser microdissection-assisted lectin microarray has been used to obtain quantitative and qualitative information on glycans on proteins expressed in microscopic regions of formalin-fixed paraffin-embedded tissue sections. For the effective visualization of this "tissue glycome mapping" data, a novel online tool, LM-GlycomeAtlas (https://glycosmos.org/lm_glycomeatlas/index), was launched in the freely available glycoscience portal, the GlyCosmos Portal (https://glycosmos.

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Mucin-type O-glycans are involved in cancer initiation and progression, although details of their biological and clinicopathological roles remain unclear. The aim of this study was to investigate the clinicopathological significance of β1,3-N-acetylglucosaminyltransferase 6 (β3Gn-T6), an essential enzyme for the synthesis of core 3 O-glycan and several other O-glycans in pancreatic ductal adenocarcinoma (PDAC). We performed immunohistochemical and lectin-histochemical analyses to detect the expression of β3Gn-T6 and several O-glycans in 156 cases of PDAC with pancreatic intraepithelial neoplasias (PanINs) and corresponding normal tissue samples.

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Glycans are primarily generated by "glycogenes," which consist of more than 200 genes for glycosynthesis, including sugar-nucleotide synthases, sugar-nucleotide transporters, and glycosyltransferases. Measuring the expression level of glycogenes is one of the approaches to analyze the glycomes of particular biological and clinical samples. To develop an effective strategy for identifying the glycosylated biomarkers, we performed transcriptome analyses using quantitative real-time polymerase chain reaction (qRT-PCR) arrays and RNA sequencing (RNA-Seq).

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Aim: Hepatitis B virus (HBV) relies on glycosylation for crucial functions, such as entry into host cells, proteolytic processing and protein trafficking. The aim of this study was to identify candidate molecules for the development of novel antiviral agents against HBV using an siRNA screening system targeting the host glycosylation pathway.

Methods: HepG2.

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Background: Aberrant glycosylation has been reported to play important roles in progression of cholangiocarcinoma (CCA) and hence the aberrant expressed glycans are beneficial markers for diagnosis and prognostic prediction of CCA.

Methods: Five CCA-associated glycobiomarkers-carbohydrate antigen 19-9 (CA19-9), carbohydrate antigen-S27 (CA-S27), CCA-associated carbohydrate antigen (CCA-CA), WFA-positive MUC1 (WFA-MUC1), and WFA-positive M2BP (WFA-M2BP), in the sera from CCA patients (N = 138) were determined in comparison with non-CCA control subjects (N = 246).

Results: Receiver operating characteristic analysis suggested the significance of each glycobiomarker in discriminating CCA from non-CCA with area under curve of 0.

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Article Synopsis
  • The study focuses on understanding the biological roles of protein glycosylation and its changes in diseases by examining the glycan structures present in various tissues and cells.
  • Researchers developed a method called laser microdissection-assisted lectin microarray (LMA) for high-throughput glycomic profiling, analyzing nine different tissues from two mice.
  • The resulting dataset, accessible through an online tool called "LM-GlyomeAtlas," allows users to compare glycomic profiles, facilitating further research on glycosylation patterns across different tissues and enhancing the existing GlycomeAtlas resource.
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The type-I LacdiNAc (LDN; GalNAcβ1-3GlcNAc) has rarely been observed in mammalian cells except in the -glycan of α-dystroglycan, in contrast to type-II LDN structures (GalNAcβ1-4GlcNAc) in - and -glycans that are present in many mammalian glycoproteins, such as pituitary and hypothalamic hormones. Although a β1,3--acetylgalactosaminyltransferase 2 (B3GALNT2; type-I LDN synthase) has been cloned, the function of type-I LDN in mammalian cells is still unclear, as its carrier protein(s) has not been identified. In this study, using HeLa cells, we demonstrate that inhibition of Golgi-resident glycosyltransferase increases the abundance of B3GALNT2-synthesized type-I LDN structures, recognized by agglutinin (WFA).

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Hepatitis B virus (HBV) is a double-stranded DNA virus composed of three types of viral particles. The virions are called Dane particles and the others are noninfectious subviral particles (SVPs). In blood, SVPs are detected in abundance, about 1000-10000 fold higher than Dane particles.

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Chst10 adds sulfate to glucuronic acid to form a carbohydrate antigen, HNK-1, in glycoproteins and glycolipids. To determine the role of Chst10 in vivo, we generated systemic Chst10-deficient mutant mice. Although Chst10(-/-) mice were born and grew to adulthood with no gross defects, they were subfertile.

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Glycans of α-dystroglycan (α-DG), which is expressed at the epithelial cell-basement membrane (BM) interface, play an essential role in epithelium development and tissue organization. Laminin-binding glycans on α-DG expressed on cancer cells suppress tumor progression by attenuating tumor cell migration from the BM. However, mechanisms controlling laminin-binding glycan expression are not known.

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Astrocytic tumor is the most prevalent primary brain tumor. However, the role of cell surface carbohydrates in astrocytic tumor invasion is not known. In a previous study, we showed that polysialic acid facilitates astrocytic tumor invasion and thereby tumor progression.

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Article Synopsis
  • * It is produced by the enzymes ST8SiaII and ST8SiaIV and is important for processes like cell survival, migration, neuronal guidance, and synapse formation.
  • * The study aims to investigate the roles of polysialic acid by analyzing neural stem cells from mice lacking polysialic acid and NCAM, providing methods for preparing and studying these cells in a lab setting.
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Alpha-dystroglycan (alpha-DG) represents a highly glycosylated cell surface molecule that is expressed in the epithelial cell-basement membrane (BM) interface and plays an essential role in epithelium development and tissue organization. The alpha-DG-mediated epithelial cell-BM interaction is often impaired in invasive carcinomas, yet roles and underlying mechanisms of such an impaired interaction in tumor progression remain unclear. We report here a suppressor function of laminin-binding glycans on alpha-DG in tumor progression.

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It is widely reported that derivatives of sugar moieties can be used to metabolically label cell surface carbohydrates or inhibit a particular glycosylation. However, few studies address the effect of substitution of the cytidylmonophosphate (CMP) portion on sialyltransferase activities. Here we first synthesized 2'-O-methyl CMP and 5-methyl CMP and then asked if these CMP derivatives are recognized by alpha2,3-sialyltransferases (ST3Gal-III and ST3Gal-IV), alpha2,6-sialyltransferase (ST6Gal-I), and alpha2,8-sialyltransferase (ST8Sia-II, ST8Sia-III, and ST8Sia-IV).

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Polysialic acid, which is synthesized by two polysialyltransferases, ST8SiaII and ST8SiaIV, plays an essential role in brain development by modifying the neural cell adhesion molecule (NCAM). It is currently unclear how polysialic acid functions in different processes of neural development. Here we generated mice doubly mutant in both ST8SiaII and ST8SiaIV to determine the effects of loss of polysialic acid on brain development.

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Article Synopsis
  • Recent studies highlight the crucial role of carbohydrates synthesized by glycosyltransferases in central nervous system development, particularly focusing on polysialic acid and its influence on neural cell interactions.
  • Polysialic acid is produced by two specific enzymes, ST8SiaII and ST8SiaIV, which have distinct spatiotemporal patterns and functions during brain development.
  • The chapter details methods for investigating the effects of these enzymes by analyzing knockout mice and utilizing immunohistochemistry techniques on brain tissues and neurons.
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