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Inoue D, Hoshino H, Chen YY, Yamamoto M, Kogami A, Fukushima M, Khoo KH, Akama TO, Yoshida Y, Kobayashi M. Structural Elucidation and Prognostic Relevance of 297-11A-Sulfated Glycans in Ovarian Carcinoma. J Transl Med 2024; 104:102057. [PMID: 38582455 DOI: 10.1016/j.labinv.2024.102057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 04/08/2024] Open
Abstract
Ovarian carcinoma is usually diagnosed at an advanced stage with peritoneal dissemination and/or lymph node metastasis, and the prognosis for such advanced carcinoma is very poor. Therefore, new biomarkers to predict patient prognosis are needed. Miyamoto et al. previously showed that keratan sulfate (KS) detected by the 5D4 monoclonal antibody was expressed in ovarian carcinoma. However, the detailed structure of such KS was not determined, and the biological significance of this finding remained to be clarified. We previously generated the 297-11A monoclonal antibody, which recognizes galactose (Gal)-6-O-sulfated N-acetyllactosamine (LacNAc) located at the nonreducing terminus. Because the 297-11A epitope overlaps with that of 5D4, here we chose to use the 297-11A antibody as a tool to analyze KS and related structures. We conducted immunohistochemical analysis of 98 ovarian carcinoma cases with 297-11A antibody combined with a series of glycosidases and performed mass spectrometry analysis of the human serous ovarian carcinoma cell line OVCAR-3 to deduce the glycan structure of 297-11A-sulfated glycans. We also performed western blot analysis to assess a potential association of 297-11A-sulfated glycans with the mucin core protein mucin 16 (MUC16; also known as cancer antigen 125 (CA125)). Finally, we examined the relationship between 297-11A expression and patient prognosis. Consequently, 297-11A-sulfated glycans were primarily expressed in serous and endometrioid carcinomas and poorly expressed in mucinous and clear cell carcinomas. We reveal that structurally, 297-11A-sulfated glycans expressed in ovarian carcinoma are O-glycans carrying partially sialylated, Gal-6-O-sulfated LacNAc and that these glycans are likely displayed on MUC16 mucin core proteins. Of clinical importance is that expression of 297-11A-sulfated glycans correlated with shorter progression-free survival in patients. Thus, 297-11A-sulfated glycans may serve as a predictor of ovarian carcinoma recurrence.
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Affiliation(s)
- Daisuke Inoue
- Department of Tumor Pathology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan; Department of Obstetrics and Gynecology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan
| | - Hitomi Hoshino
- Department of Tumor Pathology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan
| | - Ya-Ying Chen
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Makoto Yamamoto
- Department of Obstetrics and Gynecology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan
| | - Akiya Kogami
- Department of Tumor Pathology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan
| | - Mana Fukushima
- Department of Tumor Pathology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan
| | - Kay-Hooi Khoo
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan; Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Tomoya O Akama
- Department of Pharmacology, Kansai Medical University, Hirakata, Japan
| | - Yoshio Yoshida
- Department of Obstetrics and Gynecology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan
| | - Motohiro Kobayashi
- Department of Tumor Pathology, Faculty of Medical Sciences, University of Fukui, Eiheiji, Japan.
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Yasuoka Y. Tissue-specific expression of carbohydrate sulfotransferases drives keratan sulfate biosynthesis in the notochord and otic vesicles of Xenopus embryos. Front Cell Dev Biol 2023; 11:957805. [PMID: 36998246 PMCID: PMC10043435 DOI: 10.3389/fcell.2023.957805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 02/24/2023] [Indexed: 03/16/2023] Open
Abstract
Keratan sulfate (KS) is a glycosaminoglycan that is enriched in vertebrate cornea, cartilage, and brain. During embryonic development, highly sulfated KS (HSKS) is first detected in the developing notochord and then in otic vesicles; therefore, HSKS has been used as a molecular marker of the notochord. However, its biosynthetic pathways and functional roles in organogenesis are little known. Here, I surveyed developmental expression patterns of genes related to HSKS biosynthesis in Xenopus embryos. Of these genes, the KS chain-synthesizing glycosyltransferase genes, beta-1,3-N-acetylglucosaminyltransferase (b3gnt7) and beta-1,4-galactosyltransferase (b4galt4), are strongly expressed in the notochord and otic vesicles, but also in other tissues. In addition, their notochord expression is gradually restricted to the posterior end at the tailbud stage. In contrast, carbohydrate sulfotransferase (Chst) genes, chst2, chst3, and chst5.1, are expressed in both notochord and otic vesicles, whereas chst1, chst4/5-like, and chst7 are confined to otic vesicles. Because the substrate for Chst1 and Chst3 is galactose, while that for others is N-acetylglucosamine, combinatorial, tissue-specific expression patterns of Chst genes should be responsible for tissue-specific HSKS enrichment in embryos. As expected, loss of function of chst1 led to loss of HSKS in otic vesicles and reduction of their size. Loss of chst3 and chst5.1 resulted in HSKS loss in the notochord. These results reveal that Chst genes are critical for HSKS biosynthesis during organogenesis. Being hygroscopic, HSKS forms “water bags” in embryos to physically maintain organ structures. In terms of evolution, in ascidian embryos, b4galt and chst-like genes are also expressed in the notochord and regulate notochord morphogenesis. Furthermore, I found that a chst-like gene is also strongly expressed in the notochord of amphioxus embryos. These conserved expression patterns of Chst genes in the notochord of chordate embryos suggest that Chst is an ancestral component of the chordate notochord.
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Affiliation(s)
- Yuuri Yasuoka
- Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- *Correspondence: Yuuri Yasuoka, ,
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Dai Z, Wang K, Gao Y. The critical role of B4GALT4 in promoting microtubule spindle assembly in HCC through the regulation of PLK1 and RHAMM expression. J Cell Physiol 2022; 237:617-636. [PMID: 34270095 DOI: 10.1002/jcp.30531] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/18/2021] [Accepted: 07/07/2021] [Indexed: 12/20/2022]
Abstract
Beta 1,4-galactosyltransferase (B4GALT)-family glycosyltransferases are involved in multiple biological processes promoting cancer progression, regulating the dynamic network of cancer cell proliferation and apoptosis, and are associated with metastasis. However, their roles in the dysregulation of expressions and functions in hepatocellular carcinoma (HCC) remain unclear. Herein, bioinformatic approaches have been applied to investigate their expression profiles, and to obtain correlations between gene expressions and clinicopathological parameters as well as downstream target genes in HCC. Multiple databases were used to screen the expressions of B4GALT family members in tumor tissues, and to evaluate their prognostic value among HCC patients in different aspects. Results indicated an overall upregulation of B4GALTs' transcription levels in tumor tissues and a strong correlation with poor prognosis. Through Gene Ontology analysis, gene set enrichment analysis, and verification of single-cell RNA sequencing data, we established a connection between the B4GALT family and microtubule spindle assembly, which particularly highlighted the role of B4GALT4 in this phenomenon. B4GALT4 knockdown downregulated the production of lumican, and repressed the expressions of polo-like kinase 1 and RHAMM by regulating the transforming growth factor-beta pathway, thus suggesting that B4GALT4 is a critical promotor for HCC. We believe that these studies will provide valuable insight into the role of B4GALT family members in HCC and lead to the development of new strategies to improve the outcomes for patients with HCC.
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Affiliation(s)
- Zhe Dai
- Department of Biochemistry, Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Jilin University, Changchun, China
| | - Kun Wang
- Division of Obstetrics, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Yin Gao
- Department of Biochemistry, Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Jilin University, Changchun, China
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Haouari W, Dubail J, Poüs C, Cormier-Daire V, Bruneel A. Inherited Proteoglycan Biosynthesis Defects-Current Laboratory Tools and Bikunin as a Promising Blood Biomarker. Genes (Basel) 2021; 12:genes12111654. [PMID: 34828260 PMCID: PMC8625474 DOI: 10.3390/genes12111654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/11/2021] [Accepted: 10/17/2021] [Indexed: 12/15/2022] Open
Abstract
Proteoglycans consist of proteins linked to sulfated glycosaminoglycan chains. They constitute a family of macromolecules mainly involved in the architecture of organs and tissues as major components of extracellular matrices. Some proteoglycans also act as signaling molecules involved in inflammatory response as well as cell proliferation, adhesion, and differentiation. Inborn errors of proteoglycan metabolism are a group of orphan diseases with severe and irreversible skeletal abnormalities associated with multiorgan impairments. Identifying the gene variants that cause these pathologies proves to be difficult because of unspecific clinical symptoms, hardly accessible functional laboratory tests, and a lack of convenient blood biomarkers. In this review, we summarize the molecular pathways of proteoglycan biosynthesis, the associated inherited syndromes, and the related biochemical screening techniques, and we focus especially on a circulating proteoglycan called bikunin and on its potential as a new biomarker of these diseases.
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Affiliation(s)
- Walid Haouari
- INSERM UMR1193, Paris-Saclay University, Faculté de Pharmacie, 5 rue Jean-Baptiste Clément, 92220 Châtenay-Malabry, France; (W.H.); (C.P.)
| | - Johanne Dubail
- INSERM UMR1163, French Reference Center for Skeletal Dysplasia, Imagine Institute, Paris University, 24 Boulevard du Montparnasse, 75015 Paris, France; (J.D.); (V.C.-D.)
- AP-HP, Necker Enfants Malades Hospital, 149 rue de Sèvres, 75015 Paris, France
| | - Christian Poüs
- INSERM UMR1193, Paris-Saclay University, Faculté de Pharmacie, 5 rue Jean-Baptiste Clément, 92220 Châtenay-Malabry, France; (W.H.); (C.P.)
| | - Valérie Cormier-Daire
- INSERM UMR1163, French Reference Center for Skeletal Dysplasia, Imagine Institute, Paris University, 24 Boulevard du Montparnasse, 75015 Paris, France; (J.D.); (V.C.-D.)
- AP-HP, Necker Enfants Malades Hospital, 149 rue de Sèvres, 75015 Paris, France
| | - Arnaud Bruneel
- INSERM UMR1193, Paris-Saclay University, Faculté de Pharmacie, 5 rue Jean-Baptiste Clément, 92220 Châtenay-Malabry, France; (W.H.); (C.P.)
- AP-HP, Biochimie Métabolique et Cellulaire, Hôpital Bichat-Claude Bernard, 46 rue Henri Huchard, 75018 Paris, France
- Correspondence:
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Huang YF, Mizumoto S, Fujita M. Novel Insight Into Glycosaminoglycan Biosynthesis Based on Gene Expression Profiles. Front Cell Dev Biol 2021; 9:709018. [PMID: 34552927 PMCID: PMC8450405 DOI: 10.3389/fcell.2021.709018] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 08/18/2021] [Indexed: 01/11/2023] Open
Abstract
Glycosaminoglycans (GAGs) including chondroitin sulfate, dermatan sulfate, heparan sulfate, and keratan sulfate, except for hyaluronan that is a free polysaccharide, are covalently attached to core proteins to form proteoglycans. More than 50 gene products are involved in the biosynthesis of GAGs. We recently developed a comprehensive glycosylation mapping tool, GlycoMaple, for visualization and estimation of glycan structures based on gene expression profiles. Using this tool, the expression levels of GAG biosynthetic genes were analyzed in various human tissues as well as tumor tissues. In brain and pancreatic tumors, the pathways for biosynthesis of chondroitin and dermatan sulfate were predicted to be upregulated. In breast cancerous tissues, the pathways for biosynthesis of chondroitin and dermatan sulfate were predicted to be up- and down-regulated, respectively, which are consistent with biochemical findings published in the literature. In addition, the expression levels of the chondroitin sulfate-proteoglycan versican and the dermatan sulfate-proteoglycan decorin were up- and down-regulated, respectively. These findings may provide new insight into GAG profiles in various human diseases including cancerous tumors as well as neurodegenerative disease using GlycoMaple analysis.
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Affiliation(s)
- Yi-Fan Huang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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Mizumoto S, Yamada S. Congenital Disorders of Deficiency in Glycosaminoglycan Biosynthesis. Front Genet 2021; 12:717535. [PMID: 34539746 PMCID: PMC8446454 DOI: 10.3389/fgene.2021.717535] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/12/2021] [Indexed: 12/04/2022] Open
Abstract
Glycosaminoglycans (GAGs) including chondroitin sulfate, dermatan sulfate, and heparan sulfate are covalently attached to specific core proteins to form proteoglycans, which are distributed at the cell surface as well as in the extracellular matrix. Proteoglycans and GAGs have been demonstrated to exhibit a variety of physiological functions such as construction of the extracellular matrix, tissue development, and cell signaling through interactions with extracellular matrix components, morphogens, cytokines, and growth factors. Not only connective tissue disorders including skeletal dysplasia, chondrodysplasia, multiple exostoses, and Ehlers-Danlos syndrome, but also heart and kidney defects, immune deficiencies, and neurological abnormalities have been shown to be caused by defects in GAGs as well as core proteins of proteoglycans. These findings indicate that GAGs and proteoglycans are essential for human development in major organs. The glycobiological aspects of congenital disorders caused by defects in GAG-biosynthetic enzymes including specific glysocyltransferases, epimerases, and sulfotransferases, in addition to core proteins of proteoglycans will be comprehensively discussed based on the literature to date.
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Affiliation(s)
- Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan
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N-glycosylation of the human β1,4-galactosyltransferase 4 is crucial for its activity and Golgi localization. Glycoconj J 2020; 37:577-588. [PMID: 32827291 PMCID: PMC7501111 DOI: 10.1007/s10719-020-09941-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/05/2020] [Accepted: 08/13/2020] [Indexed: 12/19/2022]
Abstract
β1,4-galactosyltransferase 4 (B4GalT4) is one of seven B4GalTs that belong to CAZy glycosyltransferase family 7 and transfer galactose to growing sugar moieties of proteins, glycolipids, glycosaminoglycans as well as single sugar for lactose synthesis. Herein, we identify two asparagine-linked glycosylation sites in B4GalT4. We found that mutation of one site (Asn220) had greater impact on enzymatic activity while another (Asn335) on Golgi localization and presence of N-glycans at both sites is required for production of stable and enzymatically active protein and its secretion. Additionally, we confirm B4GalT4 involvement in synthesis of keratan sulfate (KS) by generating A375 B4GalT4 knock-out cell lines that show drastic decrease in the amount of KS proteoglycans and no significant structural changes in N- and O-glycans. We show that KS decrease in A375 cells deficient in B4GalT4 activity can be rescued by overproduction of either partially or fully glycosylated B4GalT4 but not with N-glycan-depleted B4GalT4 version.
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Gonzalez-Gil A, Porell RN, Fernandes SM, Wei Y, Yu H, Carroll DJ, McBride R, Paulson JC, Tiemeyer M, Aoki K, Bochner BS, Schnaar RL. Sialylated keratan sulfate proteoglycans are Siglec-8 ligands in human airways. Glycobiology 2019; 28:786-801. [PMID: 29924315 PMCID: PMC6142871 DOI: 10.1093/glycob/cwy057] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/18/2018] [Indexed: 01/02/2023] Open
Abstract
Human siglecs are a family of 14 sialic acid-binding proteins, most of which are expressed on subsets of immune cells where they regulate immune responses. Siglec-8 is expressed selectively on human allergic inflammatory cells—primarily eosinophils and mast cells—where engagement causes eosinophil apoptosis and inhibits mast cell mediator release. Evidence supports a model in which human eosinophils and mast cells bind to Siglec-8 sialoglycan ligands on inflammatory target tissues to resolve allergic inflammation and limit tissue damage. To identify Siglec-8-binding sialoglycans from human airways, proteins extracted from postmortem human trachea were resolved by size-exclusion chromatography and composite agarose–acrylamide gel electrophoresis, blotted and probed by Siglec-8-Fc blot overlay. Three size classes of Siglec-8 ligands were identified: 250 kDa, 600 kDa and 1 MDa, each of which was purified by affinity chromatography using a recombinant pentameric form of Siglec-8. Proteomic mass spectrometry identified all size classes as the proteoglycan aggrecan, a finding validated by immunoblotting. Glycan array studies demonstrated Siglec-8 binding to synthetic glycans with a terminal Neu5Acα2-3(6-sulfo)-Gal determinant, a quantitatively minor terminus on keratan sulfate (KS) chains of aggrecan. Treating human tracheal extracts with sialidase or keratanase eliminated Siglec-8 binding, indicating sialylated KS chains as Siglec-8-binding determinants. Treating human tracheal histological sections with keratanase also completely eliminated the binding of Siglec-8-Fc. Finally, Siglec-8 ligand purified from human trachea extracts induced increased apoptosis of freshly isolated human eosinophils in vitro. We conclude that sialylated KS proteoglycans are endogenous human airway ligands that bind Siglec-8 and may regulate allergic inflammation.
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Affiliation(s)
- Anabel Gonzalez-Gil
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ryan N Porell
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Steve M Fernandes
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yadong Wei
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Huifeng Yu
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Daniela J Carroll
- Department of Medicine, Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Ryan McBride
- Departments of Chemical Physiology, Cell and Molecular Biology, and Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA
| | - James C Paulson
- Departments of Chemical Physiology, Cell and Molecular Biology, and Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA
| | - Michael Tiemeyer
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Kazuhiro Aoki
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Bruce S Bochner
- Department of Medicine, Division of Allergy and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Caterson B, Melrose J. Keratan sulfate, a complex glycosaminoglycan with unique functional capability. Glycobiology 2018; 28:182-206. [PMID: 29340594 PMCID: PMC5993099 DOI: 10.1093/glycob/cwy003] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Revised: 12/20/2017] [Accepted: 01/08/2018] [Indexed: 12/19/2022] Open
Abstract
From an evolutionary perspective keratan sulfate (KS) is the newest glycosaminoglycan (GAG) but the least understood. KS is a sophisticated molecule with a diverse structure, and unique functional roles continue to be uncovered for this GAG. The cornea is the richest tissue source of KS in the human body but the central and peripheral nervous systems also contain significant levels of KS and a diverse range of KS-proteoglycans with essential functional roles. KS also displays important cell regulatory properties in epithelial and mesenchymal tissues and in bone and in tumor development of diagnostic and prognostic utility. Corneal KS-I displays variable degrees of sulfation along the KS chain ranging from non-sulfated polylactosamine, mono-sulfated and disulfated disaccharide regions. Skeletal KS-II is almost completely sulfated consisting of disulfated disaccharides interrupted by occasional mono-sulfated N-acetyllactosamine residues. KS-III also contains highly sulfated KS disaccharides but differs from KS-I and KS-II through 2-O-mannose linkage to serine or threonine core protein residues on proteoglycans such as phosphacan and abakan in brain tissue. Historically, the major emphasis on the biology of KS has focused on its sulfated regions for good reason. The sulfation motifs on KS convey important molecular recognition information and direct cell behavior through a number of interactive proteins. Emerging evidence also suggest functional roles for the poly-N-acetyllactosamine regions of KS requiring further investigation. Thus further research is warranted to better understand the complexities of KS.
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Affiliation(s)
- Bruce Caterson
- Connective Tissue Biology Laboratories, School of Biosciences, College of Biological & Life Sciences, Cardiff University, Cardiff, Wales, UK
| | - James Melrose
- Raymond Purves Bone and Joint Research Laboratory, Kolling Institute of Medical Research, Northern Sydney Local Health District, St. Leonards, NSW, Australia
- Sydney Medical School, Northern, The University of Sydney, Royal North Shore Hospital, St. Leonards, NSW, Australia
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
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Sugiyama A, Fukushima N, Sato T. Transcriptional Mechanism of the β4-Galactosyltransferase 4 Gene in SW480 Human Colon Cancer Cell Line. Biol Pharm Bull 2017; 40:733-737. [PMID: 28228616 DOI: 10.1248/bpb.b17-00064] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased expression of β4-galactosyltransferase (β4GalT) 4 has been shown to be associated with metastatic ability and poor prognosis of colon cancer cells. To solve the up-regulation of β4GalT4 in colon cancer cells at transcriptional level, we examined the transcriptional mechanism of the β4GalT4 gene in SW480 human colon cancer cell line. Luciferase assay using the deletion constructs revealed that the promoter activity of the β4GalT4 gene is associated with the region between nucleotides -122 and -55 relative to the transcriptional start site, which contained one Specificity protein 1 (Sp1)-binding site. The mutation into the Sp1-binding site resulted in dramatic decreased promoter activity. Meanwhile, ectopic Sp1 expression stimulated the promoter activity significantly. The present study suggests that the expression of the β4GalT4 gene is controlled by Sp1, and Sp1 plays a key role in the activation of the β4GalT4 gene in colon cancer cells.
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Affiliation(s)
- Atena Sugiyama
- Laboratory of Glycobiology, Department of Bioengineering, Nagaoka University of Technology
| | - Naomichi Fukushima
- Laboratory of Glycobiology, Department of Bioengineering, Nagaoka University of Technology
| | - Takeshi Sato
- Laboratory of Glycobiology, Department of Bioengineering, Nagaoka University of Technology
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Foyez T, Takeda-Uchimura Y, Ishigaki S, Narentuya, Zhang Z, Sobue G, Kadomatsu K, Uchimura K. Microglial keratan sulfate epitope elicits in central nervous tissues of transgenic model mice and patients with amyotrophic lateral sclerosis. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:3053-65. [PMID: 26362733 DOI: 10.1016/j.ajpath.2015.07.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 07/09/2015] [Accepted: 07/14/2015] [Indexed: 12/14/2022]
Abstract
The functional role of 5D4 antibody-reactive keratan sulfate (KS) in the pathogenesis of neurodegenerative diseases is unknown. We therefore studied the expression of 5D4-reactive KS in amyotrophic lateral sclerosis (ALS), a motor neuron-degenerative disease, with the use of SOD1(G93A) ALS model mice and patients with ALS. Histochemical and immunoelectron microscopic characterizations showed that the 5D4-reactive KS is expressed in Mac2/galectin-3-positive activated or proliferating microglia of SOD1(G93A) ALS model mice at disease end stage and that the KS is an O-linked glycan modified with sialic acid and fucose, which was thus far shown to exist in cartilage. Intriguingly, microglial KS was detected in the spinal cord and brainstem but not in the cerebral cortex of SOD1(G93A) mice. We found that KSGal6ST, a galactose-6-sulfotransferase, is required for biosynthesis of the microglial 5D4-reactive KS by generating SOD1(G93A)/KSGal6ST(-/-) mice. The requirement of GlcNAc6ST1 for this synthesis was corroborated by analyzing SOD1(G93A)/GlcNAc6ST1(-/-) mice. These results indicate that both galactose-6- and N acteylglucosamine-6-sulfated KS elicited in the spinal cord and brainstem are associated with the degeneration of spinal and bulbar lower motor neurons in ALS pathology and may play a role in disease progression via microglial activation and proliferation.
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Affiliation(s)
- Tahmina Foyez
- Department of Biochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | | | - Shinsuke Ishigaki
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Narentuya
- Department of Biochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Zui Zhang
- Department of Biochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Gen Sobue
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kenji Kadomatsu
- Department of Biochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Kenji Uchimura
- Department of Biochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan.
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Lu CH, Wu WY, Lai YJ, Yang CM, Yu LC. Suppression of B3GNT7 gene expression in colon adenocarcinoma and its potential effect in the metastasis of colon cancer cells. Glycobiology 2014; 24:359-67. [PMID: 24418929 DOI: 10.1093/glycob/cwu002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The cell surface sialyl Lewis a (sLe(a)) and sialyl Lewis x (sLe(x)) antigens, which are built on the terminals of glyco-structures called poly-N-acetyllactosamine (LacNAc) chains, have been shown to play a critical role in the metastasis of colon cancer. In the present investigation, expression of the B3GNT7 gene, which encodes a β-1,3-N-acetylglucosaminyltransferase that mainly acts on and extends sulfated poly-LacNAc chains, was found to be markedly suppressed during the oncogenetic processes associated with colon cancer. DNA methylation in the promoter region of the B3GNT7 gene was found to play a significant role in the suppression of the B3GNT7 gene in colon cancer cells. The results obtained from Transwell experiments and the nude mice xenograft model demonstrated that ectopic expression of the B3GNT7 gene in colon cancer cells diminished the migration capability and the liver-metastasis potential, respectively, of colon cancer cells. Flow cytometric analysis showed that expression of cell surface sLe(a) and sLe(x) antigens was decreased in colon cancer cells when the B3GNT7 gene was ectopically expressed. Taken together, the results of the present investigation suggest a link between suppression of B3GNT7 gene expression and elevation of sLe(a)/sLe(x) antigen expressions on the surface of cells and that this consequently promotes the metastasis potential of cancer cells as part of the colon cancer oncogenetic process.
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Affiliation(s)
- Chun-Hao Lu
- Institute of Biochemical Sciences, College of Life Science, National Taiwan University, No. 1, Roosevelt Road Sec. 4, Taipei 106, Taiwan
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Ramakrishnan B, Moncrief AJ, Davis TA, Holland LA, Qasba PK. Investigations on β1,4-galactosyltransferase I using 6-sulfo-GlcNAc as an acceptor sugar substrate. Glycoconj J 2013; 30:835-42. [PMID: 23942731 DOI: 10.1007/s10719-013-9488-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 06/18/2013] [Accepted: 07/12/2013] [Indexed: 11/28/2022]
Abstract
6-sulfate modified N-acetylglucosamine (6-sulfo-GlcNAc) is often found as part of many biologically important carbohydrate epitopes such as 6-sulfo-Le(X). In these epitopes, the 6-sulfo-GlcNAc moiety is extended by a galactose sugar in a β1-4 linkage. The β4GalT1 enzyme transfers galactose (Gal) from UDP-Gal to N-acetylglucosamine (GlcNAc) in the presence of manganese. Here we report that the β4GalT1 enzyme transfers Gal to the 6-sulfo-GlcNAc and 4-methylumbelliferyl-6-sulfo-N-acetyl-β-D-glucosaminide (6-sulfo-βGlcNAc-MU) acceptor substrates, although with very low efficiency. To understand the effect that the 6-sulfate group on the GlcNAc acceptor has on the catalytic activity of the β4GalT1 molecule, we have determined the crystal structure of the catalytic domain of bovine β4GalT1 mutant enzyme M344H-β4GalT1 complex with the 6-sulfo-GlcNAc molecule. In the crystal structure, the 6-sulfo-GlcNAc is bound to the protein in a way that is similar to the GlcNAc molecule. However, the 6-sulfate group engages in additional interactions with the hydrophobic region, residues 276-285, of the protein molecule, and this group is found wedged between the aromatic side chains of Phe-280 and Trp314 residues. Since the side chain of the Trp314 residue undergoes conformational changes during the catalytic cycle of the enzyme, molecular interaction between Trp314 and the 6-sulfate group might hinder this conformational change. Therefore, the lack of a favorable binding environment, together with hindrance to the conformational changes, might be responsible for the poor catalytic activity.
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Affiliation(s)
- Boopathy Ramakrishnan
- Structural Glycobiology Section, Basic Science Laboratory, National Cancer Institute at Frederick, P.O. Box B, Frederick, MD, 21702, USA
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Block H, Ley K, Zarbock A. Severe impairment of leukocyte recruitment in ppGalNAcT-1-deficient mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 188:5674-81. [PMID: 22544932 DOI: 10.4049/jimmunol.1200392] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
P-selectin glycoprotein ligand-1 plays an important role in leukocyte recruitment. Its binding affinity to selectins is modulated by posttranslational modifications. The polypeptide N-acetylgalactosamine transferase-1 (ppGalNAcT-1) initiates core-type protein O-glycosylation. To address whether the glycosylation of P-selectin glycoprotein ligand-1 by ppGalNAcT-1 is important for leukocyte recruitment in vivo, we investigated leukocyte recruitment in untreated and TNF-α-treated cremaster muscles comparing ppGalNAcT-1-deficient mice (Galnt1(-/-)) and wild-type mice. In untreated and TNF-α-treated Galnt1(-/-) mice, leukocyte rolling, adhesion, and transmigration were significantly reduced, with markedly increased rolling velocity compared with control mice. L-selectin-dependent leukocyte rolling was completely abolished in Galnt1(-/-) mice compared with wild-type mice. Thioglycollate-induced peritonitis experiments with chimeric mice revealed that hematopoietic ppGalNAcT-1 is important for leukocyte recruitment. These data show that the loss of ppGalNAcT-1 led to reduced leukocyte rolling and recruitment and increased rolling velocity, suggesting a predominant role for ppGalNAcT-1 in attaching functionally relevant O-linked glycans to selectin ligands.
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Affiliation(s)
- Helena Block
- Department of Anesthesiology and Intensive Care Medicine, University of Münster, 48151 Münster, Germany
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15
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Abstract
The ability of leukocytes to navigate through the different body compartments is an essential component for functioning immune defense and surveillance systems. In order to exit the blood circulation, leukocytes follow distinct recruitment steps, including capture of free-flowing leukocytes to, and rolling along, the vessel wall; firm leukocyte arrest on the endothelial lining; and postarrest modifications (spreading and crawling), which prepare the leukocyte for transmigration through the vascular wall. Post-translational glycosylation (including sialylation) has been known for many years to be functionally relevant for selectin ligands and, hence, selectin-mediated capture and rolling. Recently, sialylation by the α2-3 sialyltransferase ST3Gal-IV was identified to significantly influence chemokine-triggered firm leukocyte arrest, expanding the role of α2-3 sialylation from leukocyte rolling to subsequent chemokine-triggered leukocyte arrest. These findings make ST3Gal-IV an interesting drug target for modulating leukocyte trafficking in human disorders, including autoimmune diseases and cancer.
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Affiliation(s)
- Markus Sperandio
- Walter Brendel Center of Experimental Medicine, Ludwig-Maximilians-Universität, Munich, Germany.
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Seko A, Ohkura T, Ideo H, Yamashita K. Novel O-linked glycans containing 6'-sulfo-Gal/GalNAc of MUC1 secreted from human breast cancer YMB-S cells: possible carbohydrate epitopes of KL-6(MUC1) monoclonal antibody. Glycobiology 2011; 22:181-95. [PMID: 21880669 DOI: 10.1093/glycob/cwr118] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Human serum Krebs von den Lugen-6 (KL-6) antigen is a MUC1 glycoprotein (KL-6/MUC1) recognized by anti-KL-6 monoclonal antibody (KL-6/mAb) and has been utilized as a diagnostic marker for interstitial pneumonia. KL-6/mAb is thought to recognize the specific glycopeptides sequence of MUC1, but the precise glycan structure of the epitope is unclear. In this study, we determined the carbohydrate structures of KL-6/MUC1 to search the carbohydrate epitopes for KL-6/mAb. KL-6/MUC1 was purified from the culture medium of human breast cancer YMB-S cells by KL-6/mAb-affinity chromatography; the O-linked glycan structures were determined in combination with paper electrophoresis, several lectin column chromatographies, sialidase digestion and methanolysis. KL-6/MUC1 contained core 1 and extended core 1 glycans modified with one or two sialic acid/sulfate residues. Based on these structures, several synthetic glycans binding to anti-KL-6/mAb were compared with one another by surface plasmon resonance. Sequentially, related radiolabeled oligosaccharides were enzymatically synthesized and analyzed for binding to a KL-6/mAb-conjugated affinity column. 3'-sialylated, 6'-sulfated LNnT [Neu5Acα2-3(SO(3)(-)-6)Galβ1-4GlcNAcβ1-3Galβ1-4Glc], 3'-sialylated, 6-sulfated core 1 [Neu5Acα2-3Galβ1-3(SO(3)(-)-6)GalNAc] and disulfated core 1 SO(3)(-)-3Galβ1-3(SO(3)(-)-6)GalNAc exhibited substantial affinity for KL-6/mAb, and 3'-sulfated core 1 derivatives [SO(3)(-)-3Galβ1-3(±Neu5Acα2-6)GalNAc] and 3'-sialylated core 1 weakly interacted with KL-6/mAb. These results indicated that the possible carbohydrate epitopes of KL-6/mAb involve not only 3'-sialylated core 1 but also novel core 1 and extended core 1 with sulfate and sialic acid residues. Epitope expressing changes with suppression or over-expression of the Gal6ST (Gal 6-O-sulfotransferase) gene, suggesting that Gal6ST is involved in the biosynthesis of the unique epitopes of KL-6/mAb.
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Affiliation(s)
- Akira Seko
- Innovative Research Initiatives, Tokyo Institute of Technology, Nagatsuta-cho, Midori-ku, Yokohama, Japan
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Lau K, Thon V, Yu H, Ding L, Chen Y, Muthana MM, Wong D, Huang R, Chen X. Highly efficient chemoenzymatic synthesis of beta1-4-linked galactosides with promiscuous bacterial beta1-4-galactosyltransferases. Chem Commun (Camb) 2010; 46:6066-8. [PMID: 20625591 DOI: 10.1039/c0cc01381a] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Two bacterial beta1-4-galactosyltransferases, NmLgtB and Hp1-4GalT, exhibit promiscuous and complementary acceptor substrate specificity. They have been used in an efficient one-pot multienzyme system to synthesize LacNAc, lactose, and their derivatives including those containing negatively charged 6-O-sulfated GlcNAc and C2-substituted GlcNAc or Glc, from monosaccharide derivatives and inexpensive Glc-1-P.
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Affiliation(s)
- Kam Lau
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, USA
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18
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Nishie T, Hikimochi Y, Zama K, Fukusumi Y, Ito M, Yokoyama H, Naruse C, Ito M, Asano M. Beta4-galactosyltransferase-5 is a lactosylceramide synthase essential for mouse extra-embryonic development. Glycobiology 2010; 20:1311-22. [PMID: 20574042 DOI: 10.1093/glycob/cwq098] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Glycosphingolipids (GSLs) are important for various biological functions in the nervous system, the immune system, embryogenesis and in other tissues and processes. Lactosylceramide (LacCer), which is synthesized from glucosylceramide (GlcCer) by LacCer synthase, is a core structure of GSLs, including gangliosides. LacCer synthase was reported to be synthesized by the beta4-galactosyltransferase-6 (beta4GalT-6) gene in the rat brain. However, the existence of another LacCer synthase gene was shown in cultured cells lacking beta4GalT-6. Here, we report that LacCer synthase is mainly synthesized by the beta4GalT-5 gene during early mouse embryogenesis, and its disruption is embryonic lethal. beta4GalT-5-deficient embryos showed developmental retardation from E7.5 and died by E10.5 as reported previously. LacCer synthase activity was significantly reduced in beta4GalT-5-deficient embryos and extra-embryonic endoderm (XEN) cells derived from blastocysts, and it was recovered when beta4GalT-5 cDNA was introduced into beta4GalT-5-deficient XEN cells. The amounts of LacCer and GM3 ganglioside were drastically reduced, while GlcCer accumulated in the beta4GalT-5-deficient XEN cells. Hematoma and ectopically accumulated trophoblast giant cells were observed in the anti-mesometrial pole of the extra-embryonic tissues, although all three embryonic layers formed. beta4GalT-5-deficient embryos developed until E12.5 as chimeras with wild-type tetraploid cells, which formed the extra-embryonic membranes, indicating that extra-embryonic defects caused the early embryonic lethality. Our results suggest that beta4GalT-5 is essential for extra-embryonic development during early mouse embryogenesis.
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Affiliation(s)
- Toshikazu Nishie
- Division of Transgenic Animal Science, Advanced Science Research Center, Kanazawa University, Kanazawa, Japan
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Quantock AJ, Young RD, Akama TO. Structural and biochemical aspects of keratan sulphate in the cornea. Cell Mol Life Sci 2010; 67:891-906. [PMID: 20213925 PMCID: PMC11115788 DOI: 10.1007/s00018-009-0228-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 12/02/2009] [Accepted: 12/04/2009] [Indexed: 12/13/2022]
Abstract
Keratan sulphate (KS) is the predominant glycosaminoglycan (GAG) in the cornea of the eye, where it exists in proteoglycan (PG) form. KS-PGs have long been thought to play a pivotal role in the establishment and maintenance of the array of regularly-spaced and uniformly- thin collagen fibrils which make up the corneal stroma. This characteristic arrangement of fibrils allows light to pass through the cornea. Indeed, perturbations to the synthesis of KS-PG core proteins in genetically altered mice lead to structural matrix alterations and corneal opacification. Similarly, mutations in enzymes responsible for the sulphation of KS-GAG chains are causative for the inherited human disease, macular corneal dystrophy, which is manifested clinically by progressive corneal cloudiness starting in young adulthood.
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Abstract
Leukocyte recruitment encompasses cell adhesion and activation steps that enable circulating leukocytes to roll, arrest, and firmly adhere on the endothelial surface before they extravasate into distinct tissue locations. This complex sequence of events relies on adhesive interactions between surface structures on leukocytes and endothelial cells and also on signals generated during the cell-cell contacts. Cell surface glycans play a crucial role in leukocyte recruitment. Several glycosyltransferases such as alpha1,3 fucosyltransferases, alpha2,3 sialyltransferases, core 2 N-acetylglucosaminlytransferases, beta1,4 galactosyltransferases, and polypeptide N-acetylgalactosaminyltransferases have been implicated in the generation of functional selectin ligands that mediate leukocyte rolling via binding to selectins. Recent evidence also suggests a role of alpha2,3 sialylated carbohydrate determinants in triggering chemokine-mediated leukocyte arrest and influencing beta1 integrin function. The recent discovery of galectin- and siglec-dependent processes further emphasizes the significant role of glycans for the successful recruitment of leukocytes into tissues. Advancing the knowledge on glycan function into appropriate pathology models is likely to suggest interesting new therapeutic strategies in the treatment of immune- and inflammation-mediated diseases.
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Affiliation(s)
- Markus Sperandio
- Walter Brendel Center of Experimental Medicine, Ludwig-Maximilians-Universität, Munich, Germany.
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21
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Carlow DA, Gossens K, Naus S, Veerman KM, Seo W, Ziltener HJ. PSGL-1 function in immunity and steady state homeostasis. Immunol Rev 2009; 230:75-96. [PMID: 19594630 DOI: 10.1111/j.1600-065x.2009.00797.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The substantial importance of P-selectin glycoprotein ligand 1 (PSGL-1) in leukocyte trafficking has continued to emerge beyond its initial identification as a selectin ligand. PSGL-1 seemed to be a relatively simple molecule with an extracellular mucin domain extended as a flexible rod, teleologically consistent with its primary role in tethering leukocytes to endothelial selectins. The rolling interaction between leukocyte and endothelium mediated by this selectin-PSGL-1 interaction requires branched O-glycan extensions on specific PSGL-1 amino acid residues. In some cells, such as neutrophils, the glycosyltransferases involved in formation of the O-glycans are constitutively expressed, while in other cells, such as T cells, they are expressed only after appropriate activation. Thus, PSGL-1 supports leukocyte recruitment in both innate and adaptive arms of the immune response. A complex array of amino acids within the selectins engage multiple sugar residues of the branched O-glycans on PSGL-1 and provide the molecular interactions responsible for the velcro-like catch bonds that support leukocyte rolling. Such binding of PSGL-1 can also induce signaling events that influence cell phenotype and function. Scrutiny of PSGL-1 has revealed a better understanding of how it performs as a selectin ligand and yielded unexpected insights that extend its scope from supporting leukocyte rolling in inflammatory settings to homeostasis including stem cell homing to the thymus and mature T-cell homing to secondary lymphoid organs. PSGL-1 has been found to bind homeostatic chemokines CCL19 and CCL21 and to support the chemotactic response to these chemokines. Surprisingly, the O-glycan modifications of PSGL-1 that support rolling mediated by selectins in inflammatory conditions interfere with PSGL-1 binding to homeostatic chemokines and thereby limit responsiveness to the chemotactic cues used in steady state T-cell traffic. The multi-level influence of PSGL-1 on cell traffic in both inflammatory and steady state settings is therefore substantially determined by the orchestrated addition of O-glycans. However, central as specific O-glycosylation is to PSGL-1 function, in vivo regulation of PSGL-1 glycosylation in T cells remains poorly understood. It is our purpose herein to review what is known, and not known, of PSGL-1 glycosylation and to update understanding of PSGL-1 functional scope.
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Affiliation(s)
- Douglas A Carlow
- The Biomedical Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
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Polyoxometalates as effective inhibitors for sialyl- and sulfotransferases. J Inorg Biochem 2009; 103:1061-6. [PMID: 19508952 DOI: 10.1016/j.jinorgbio.2009.05.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 04/14/2009] [Accepted: 05/06/2009] [Indexed: 11/22/2022]
Abstract
Sialylated and/or sulfated carbohydrate chains in glycoproteins and glycolipids play important roles in infection by microorganisms and diseases including cancer. Inhibitors of sialyl/sulfotransferases, responsible for the biosynthesis of these carbohydrate chains, could be medical agents against such infections and diseases. Polyoxometalates (PMs) are inorganic polyanionic molecules that have been shown to exhibit activity against tumors and infectious microorganisms; however, the effects of PMs on carbohydrate biosynthesis have never been investigated. Here, we found that some types of PMs can inhibit the enzymatic activities of specific sialyl/sulfotransferases. Several tungstate-type PMs inhibited Gal: alpha2,3-sialyltransferase-I (ST3Gal-I) activity at sub-nanomolar levels. The half-inhibitory concentration of the best inhibitors was 0.2 nM and the inhibition was non-competitive for both donor and acceptor substrates (Ki values approximately 0.5 nM). By certain vanadate-type PMs, ST3Gal-I and Gal 3-O-sulfotransferase-2 (Gal3ST-2) were specifically inhibited at nanomolar levels. The inhibitory effect of a tungstate-type PM on ST3Gal-I was reversible and electrostatic. A ST3Gal-I mutant protein which was converted (335)Arg residue in the C-terminal region to Glu, was rather insensitive to the PM, suggesting that specific C-terminal basic amino acid of ST3Gal-I is involved in the binding to PMs. Collectively, PMs are novel inhibitors of specific sialyl/sulfotransferases.
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Kato Y, Hayatsu N, Kaneko MK, Ogasawara S, Hamano T, Takahashi S, Nishikawa R, Matsutani M, Mishima K, Narimatsu H. Increased expression of highly sulfated keratan sulfate synthesized in malignant astrocytic tumors. Biochem Biophys Res Commun 2008; 369:1041-6. [PMID: 18329383 DOI: 10.1016/j.bbrc.2008.02.130] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 02/27/2008] [Indexed: 11/26/2022]
Abstract
Keratan sulfate (KS) proteoglycans are expressed on a subpopulation of microglia in normal adult brain. We previously showed the up-regulated expression of KS in one of glioblastoma cell lines using anti-KS antibody (5D4). However, it has not been clarified whether KS is expressed in brain tumors and is involved in their malignancy. In this study, 54 astrocytic tumors were investigated about KS-expression using Western-blot with 5D4. In six of 14 anaplastic astrocytomas (43%) and 23 of 34 glioblastomas (68%), KS was detected by 5D4. KS was hardly detected by 5D4 in diffuse astrocytoma, suggesting that KS-expression is significantly expressed in malignant astrocytic tumors. In immunohistochemistry, KS is highly expressed in cell surface of malignant astrocytic tumors. Taken together, KS might be associated with the malignancy of astrocytic tumors, and be useful for a prognostic factor of astrocytic tumors.
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Affiliation(s)
- Yukinari Kato
- Research Center for Medical Glycoscience (RCMG), National Institute of Advanced Industrial Science and Technology (AIST), Open Space Laboratory C-2, 1-1-1, Tsukuba, Ibaraki 305-8568, Japan
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Expression of highly sulfated keratan sulfate synthesized in human glioblastoma cells. Biochem Biophys Res Commun 2008; 368:217-22. [PMID: 18211804 DOI: 10.1016/j.bbrc.2008.01.058] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Accepted: 01/11/2008] [Indexed: 11/23/2022]
Abstract
Keratan sulfate (KS) proteoglycan is expressed in the extracellular matrix or cell surface in numerous tissues, predominantly in those of the cornea, cartilage, and brain. However, its structure, function, and regulation remain poorly understood. Our investigation of KS expression in glioblastoma cell lines using Western-blot and flow cytometry with anti-KS antibody (5D4) revealed that LN229 glioblastoma cell highly expresses KS on a cell surface. Real-time PCR analysis showed that LN229 expresses a high level of keratan sulfate Gal-6-sulfotransferase. Results of this study also demonstrate that recombinant 5D4-reactive aggrecan is produced in LN229. Taken together, these results suggest that LN229 produces 5D4-reactive highly sulfated KS and is useful to investigate the KS structure and function in glioblastoma.
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Kitayama K, Hayashida Y, Nishida K, Akama TO. Enzymes responsible for synthesis of corneal keratan sulfate glycosaminoglycans. J Biol Chem 2007; 282:30085-96. [PMID: 17690104 DOI: 10.1074/jbc.m703695200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Keratan sulfate glycosaminoglycans are among the most abundant carbohydrate components of the cornea and are suggested to play an important role in maintaining corneal extracellular matrix structure. Keratan sulfate carbohydrate chains consist of repeating N-acetyllactosamine disaccharides with sulfation on the 6-O positions of N-acetylglucosamine and galactose. Despite its importance for corneal function, the biosynthetic pathway of the carbohydrate chain and particularly the elongation steps are poorly understood. Here we analyzed enzymatic activity of two glycosyltransferases, beta1,3-N-acetylglucosaminyltansferase-7 (beta3GnT7) and beta1,4-galactosyltransferase-4 (beta4GalT4), in the production of keratan sulfate carbohydrate in vitro. These glycosyltransferases produced only short, elongated carbohydrates when they were reacted with substrate in the absence of a carbohydrate sulfotransferase; however, they produced extended GlcNAc-sulfated poly-N-acetyllactosamine structures with more than four repeats of the GlcNAc-sulfated N-acetyllactosamine unit in the presence of corneal N-acetylglucosamine 6-O sulfotransferase (CGn6ST). Moreover, we detected production of highly sulfated keratan sulfate by a two-step reaction in vitro with a mixture of beta3GnT7/beta4GalT4/CGn6ST followed by keratan sulfate galactose 6-O sulfotransferase treatment. We also observed that production of highly sulfated keratan sulfate in cultured human corneal epithelial cells was dramatically reduced when expression of beta3GnT7 or beta4GalT4 was suppressed by small interfering RNAs, indicating that these glycosyltransferases are responsible for elongation of the keratan sulfate carbohydrate backbone.
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Affiliation(s)
- Kazuko Kitayama
- Glycobiology Program, Burnham Institute for Medical Research, La Jolla, California 92037, USA
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Shamonki MI, Kligman I, Shamonki JM, Schattman GL, Hyjek E, Spandorfer SD, Zaninovic N, Rosenwaks Z. Immunohistochemical expression of endometrial L-selectin ligand is higher in donor egg recipients with embryonic implantation. Fertil Steril 2006; 86:1365-75. [PMID: 16989829 DOI: 10.1016/j.fertnstert.2006.04.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 04/09/2006] [Accepted: 04/09/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To correlate L-selectin ligand (LSL) expression in human endometrium with embryonic implantation. DESIGN Retrospective cohort analysis. SETTING University-based fertility center. PATIENT(S) Donor egg recipients (DERs) who underwent programmed hormonal replacement for ET with prior mock cycle luteal phase endometrial biopsy. INTERVENTION(S) Immunohistochemical expression of LSL using MECA-79 antibody was examined. Slides were scored with a new scoring system, the IHC-Level (range 0-4) as follows: strength of staining-absent (0), weak (1), or strong (2); plus distribution of staining-absent (0), <50% of tissue (1), and >50% (2). Cellular apex and cytoplasm were scored independently in both the endometrial glandular and surface epithelium. MAIN OUTCOME MEASURE(S) Endometrial LSL expression in pregnant versus nonpregnant patients. RESULT(S) MECA-79 IHC-Level of the apex of surface epithelium was significantly higher for pregnant versus nonpregnant DERs (3.8 vs. 3.4). When controlling for embryo morphology, there continues to be a significant difference in apex score on surface epithelium (3.8 vs. 3.3, respectively). The new scoring system results correlated with an established scoring system, the HSCORE. CONCLUSION(S) We demonstrate significantly higher expression of LSL at the apex of human endometrial surface epithelium obtained from DERs with embryonic implantation. Furthermore, we present the IHC-Level, a method of evaluating immunohistochemistry that may be applied to other markers of endometrial receptivity.
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Affiliation(s)
- Mousa I Shamonki
- The Center for Reproductive Medicine, Weill Medical College of Cornell University, New York, USA.
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Abstract
Leukocyte rolling is an important step for the successful recruitment of leukocytes into tissue and occurs predominantly in inflamed microvessels and in high endothelial venules of secondary lymphoid organs. Leukocyte rolling is mediated by a group of C-type lectins, termed selectins. Three different selectins have been identified - P-, E- and L-selectin - which recognize and bind to crucial carbohydrate determinants on selectin ligands. Among selectin ligands, P-selectin glycoprotein ligand-1 is the main inflammatory selectin ligand, showing binding to all three selectins under in vivo conditions. Functional relevant selectin ligands expressed on high endothelial venules of lymphoid tissue are less clearly defined at the protein level. However, high endothelial venule-expressed selectin ligands were instrumental in uncovering the crucial role of post-translational modifications for selectin ligand activity. Several glycosyltransferases, such as core 2 beta1,6-N-acetylglucosaminyltransferase-I, beta1,4-galactosyltransferases, alpha1,3-fucosyltransferases and alpha2,3-sialyltransferases have been described to participate in the synthesis of core 2 decorated O-glycan structures carrying the tetrasaccharide sialyl Lewis X, a carbohydrate determinant on selectin ligands with binding activity to all three selectins. In addition, modifications, such as carbohydrate or tyrosine sulfation, were also found to contribute to the synthesis of functional selectin ligands.
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Affiliation(s)
- Markus Sperandio
- University Children's Hospital Heidelberg, Division of Neonatal Medicine, University of Heidelberg, Germany.
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Habuchi H, Habuchi O, Uchimura K, Kimata K, Muramatsu T. Determination of Substrate Specificity of Sulfotransferases and Glycosyltransferases (Proteoglycans). Methods Enzymol 2006; 416:225-43. [PMID: 17113869 DOI: 10.1016/s0076-6879(06)16014-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Proteoglycans have sulfated linear polysaccharide chains, that is, heparan sulfate, heparin, chondroitin sulfates, dermatan sulfate, and keratan sulfate. Many glycosyltransferases and sulfotransferases are involved in biosynthesis of the polysaccharides. Specificities of these enzymes have been mainly determined by evaluating their activities to various acceptor carbohydrates and by analyzing the structure of the products. For the latter purpose, enzymatic hydrolysis using heparitinases, heparinase, and chondroitinases or chemical degradation employing nitrous acid deamination has been effectively used in combination with high-performance liquid chromatography (HPLC) of the degraded products. As examples, we describe methods for assays and product characterization of sulfotransferases involved in biosynthesis of these polysaccharides, namely heparan sulfate 2-sulfotransferase, heparan sulfate 6-sulfotransferases, chondroitin 4-sulfotransferases, chondroitin 6-sulfotransferase, N-acetylgalactosamine 4-sulfate 6-sulfotransferase, and N-acetylglucosamine 6-sulfotransferases.
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Affiliation(s)
- Hiroko Habuchi
- Institute for Molecular Science of Medicine, Aichi Medical University, Nagakute, Japan
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Seko A, Sumiya JI, Yamashita K. Porcine, mouse and human galactose 3-O-sulphotransferase-2 enzymes have different substrate specificities; the porcine enzyme requires basic compounds for its catalytic activity. Biochem J 2005; 391:77-85. [PMID: 15926885 PMCID: PMC1237141 DOI: 10.1042/bj20050362] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2005] [Revised: 05/19/2005] [Accepted: 05/31/2005] [Indexed: 11/17/2022]
Abstract
Sulphation of galactose at the C-3 position is one of the major post-translational modifications of colorectal mucin. Thus we partially purified a Gal 3-O-sulphotransferase from porcine colonic mucosa (pGal3ST) and studied its enzymatic characteristics. The enzyme was purified 48500-fold by sequential chromatographies on hydroxyapatite, Con A (concanavalin A)-Sepharose, porcine colonic mucin-Sepharose, Cu2+-chelating Sepharose and AMP-agarose. Interestingly, the purified pGal3ST required submillimolar concentrations of spermine or basic lipids, such as D-sphingosine and N,N-dimethylsphingosine, for enzymatic activity. pGal3ST recognized Galbeta1-->3GalNAc (core 1) as an optimal substrate, and had weaker activity for Galbeta1-->3GlcNAc (type 1) and Galbeta1-->4GlcNAc (type 2). Substrate competition experiments proved that a single enzyme catalyses sulphation of all three oligosaccharides. Among the four human Gal3STs cloned to date, the substrate specificity of pGal3ST is most similar to that of human Gal3ST-2, which is also strongly expressed in colonic mucosa, although the kinetics of pGal3ST and human Gal3ST-2 were rather different. To determine whether pGal3ST is the orthologue of human Gal3ST-2, a cDNA encoding porcine Gal3ST-2 was isolated and the enzyme was expressed in COS-7 cells for analysis of substrate specificity. This revealed that porcine Gal3ST-2 has the same specificity as pGal3ST, indicating that pGal3ST is indeed the porcine equivalent of Gal3ST-2. The substrate specificity of mouse Gal3ST-2 was also different from those of human and porcine Gal3ST-2 enzymes. Mouse Gal3ST-2 preferred core 1 and type 2 glycans to type 1, and the K(m) values were much higher than those of human Gal3ST-2. These results suggest that porcine Gal3ST-2 requires basic compounds for catalytic activity and that human, mouse and porcine Gal3ST-2 orthologues have diverse substrate specificities.
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Key Words
- colonic mucosa
- mucin
- spermine
- sphingosine
- sulphotransferase
- bigp, galβ1→4glcnacβ1→2manα1→3(galβ1→4glcnacβ1→2manα1→6)manβ1→4glcnacβ1→4glcnac
- bn, benzyl
- con a, concanavalin a
- core 1, galβ1→3galnacα1→
- core 2, galβ1→3(glcnacβ1→6)galnacα1→
- dtt, dithiothreitol
- galcer, galactosylceramide
- galdg, galactosyldiacylglycerol
- gal3st, gal 3-o-sulphotransferase
- laccer, lactosylceramide
- lnt, galβ1→3glcnacβ1→3galβ1→4glc
- monogp, galβ1→4glcnacβ1→2manα1→3/6manβ1→4glcnac
- paps, adenosine 3′-phosphate 5′-phosphosulphate
- pgal3st, porcine gal3st
- pna, peanut agglutinin
- pnp, p-nitrophenyl
- race, rapid amplification of cdna ends
- sult, sulphotransferase
- type 1, galβ1→3glcnac (lacto-n-biose i)
- type 2, galβ1→4glcnac (n-acetyllactosamine)
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Affiliation(s)
- Akira Seko
- *Department of Biochemistry, Sasaki Institute, 2-2, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062
- †CREST, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama, Japan
| | - Jun-ichi Sumiya
- *Department of Biochemistry, Sasaki Institute, 2-2, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062
| | - Katsuko Yamashita
- *Department of Biochemistry, Sasaki Institute, 2-2, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062
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Sasaki N, Manya H, Okubo R, Kobayashi K, Ishida H, Toda T, Endo T, Nishihara S. β4GalT-II is a key regulator of glycosylation of the proteins involved in neuronal development. Biochem Biophys Res Commun 2005; 333:131-7. [PMID: 15939404 DOI: 10.1016/j.bbrc.2005.05.082] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Accepted: 05/17/2005] [Indexed: 11/21/2022]
Abstract
Seven members of the human beta1,4-galactosyltransferase (beta4GalTs) have been identified and characterized by many groups. beta4GalTs play important roles in the extension of N- and O-linked glycans involved in several biological events. However, it has not been clear which beta4GalTs can act on glycoproteins, such as alpha-dystroglycan and Notch receptors, involved in neuronal development. To clarify which beta4GalTs can function, we determined the enzyme activities toward such motifs and the transcript levels in human normal tissues. Among human beta4GalTs, both beta4GalT-I and beta4GalT-II could act efficiently on all substrates, but the relative activity of beta4GalT-II was higher than that of beta4GalT-I. Transcript of beta4GalT-I was widely expressed except for brain, and on the other hand, that of beta4GalT-II was expressed at high levels in the brain. Thus, these results suggest that among human beta4GalTs, beta4GalT-II is a major regulator of the synthesis of glycans involved in neuronal development.
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Affiliation(s)
- Norihiko Sasaki
- Laboratory of Cell Biology, Department of Bioinformatics, Faculty of Engineering, Soka University, Hachioji, Tokyo, Japan
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Gulberti S, Lattard V, Fondeur M, Jacquinet JC, Mulliert G, Netter P, Magdalou J, Ouzzine M, Fournel-Gigleux S. Phosphorylation and Sulfation of Oligosaccharide Substrates Critically Influence the Activity of Human β1,4-Galactosyltransferase 7 (GalT-I) and β1,3-Glucuronosyltransferase I (GlcAT-I) Involved in the Biosynthesis of the Glycosaminoglycan-Protein Linkage Region of Proteoglycans. J Biol Chem 2005; 280:1417-25. [PMID: 15522873 DOI: 10.1074/jbc.m411552200] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We determined whether the two major structural modifications, i.e. phosphorylation and sulfation of the glycosaminoglycan-protein linkage region (GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1), govern the specificity of the glycosyltransferases responsible for the biosynthesis of the tetrasaccharide primer. We analyzed the influence of C-2 phosphorylation of Xyl residue on human beta1,4-galactosyltransferase 7 (GalT-I), which catalyzes the transfer of Gal onto Xyl, and we evaluated the consequences of C-4/C-6 sulfation of Galbeta1-3Gal (Gal2-Gal1) on the activity and specificity of beta1,3-glucuronosyltransferase I (GlcAT-I) responsible for the completion of the glycosaminoglycan primer sequence. For this purpose, a series of phosphorylated xylosides and sulfated C-4 and C-6 analogs of Galbeta1-3Gal was synthesized and tested as potential substrates for the recombinant enzymes. Our results revealed that the phosphorylation of Xyl on the C-2 position prevents GalT-I activity, suggesting that this modification may occur once Gal is attached to the Xyl residue of the nascent oligosaccharide linkage. On the other hand, we showed that sulfation on C-6 position of Gal1 of the Galbeta1-3Gal analog markedly enhanced GlcAT-I catalytic efficiency and we demonstrated the importance of Trp243 and Lys317 residues of Gal1 binding site for enzyme activity. In contrast, we found that GlcAT-I was unable to use digalactosides as acceptor substrates when Gal1 was sulfated on C-4 position or when Gal2 was sulfated on both C-4 and C-6 positions. Altogether, we demonstrated that oligosaccharide modifications of the linkage region control the specificity of the glycosyltransferases, a process that may regulate maturation and processing of glycosaminoglycan chains.
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Affiliation(s)
- Sandrine Gulberti
- UMR 7561 CNRS-Université Henri Poincaré Nancy 1, Faculté de Médecine, 54505 Vandoeuvre-lès-Nancy, France
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Abstract
Understanding the molecular basis of lymphocyte homing to lymphoid organs was originally a problem of concern only to immunologists. With the discovery of L-selectin and its ligands, interested scientists have expanded to include glycobiologists, immunopathologists, cancer biologists, and developmental biologists. Going beyond its first discovered role in homing to lymph nodes, the L-selectin system is implicated in such diverse processes as inflammatory leukocyte trafficking in both acute and chronic settings, hematogenous metastasis of carcinoma cells, effector mechanisms for inflammatory demyelination of axons, and implantation of the early mammalian embryo. This review focuses on the ligands for L-selectin that are found on vascular endothelium, leukocytes, carcinoma cells, and at various extravascular sites. The discovery of selectins and their ligands has validated the long-predicted hypothesis that carbohydrate-directed cell adhesion is relevant in eukaryotic systems. Emphasis will be given to the carbohydrate and sulfation modifications of the ligands, which enable recognition by L-selectin. The rapid "homing" of labeled cells into the lymph nodes presumably had its basis in the special affinity of small lymphocytes for the endothelium of the postcapillary venules.
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Affiliation(s)
- Steven D Rosen
- Department of Anatomy and Program in Immunology, University of California, San Francisco, San Francisco, California 94143-0452, USA.
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Seko A, Yamashita K. β1,3-N-Acetylglucosaminyltransferase-7 (β3Gn-T7) acts efficiently on keratan sulfate-related glycans. FEBS Lett 2003; 556:216-20. [PMID: 14706853 DOI: 10.1016/s0014-5793(03)01440-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
beta1,3-N-Acetylglucosaminyltransferase-7 (beta3Gn-T7) has been identified as an anti-migration factor for a lung cancer cell line but its enzymatic activity has not yet been characterized. Here we show that beta3Gn-T7 efficiently acts on keratan sulfate-related glycans including Galbeta1-->4(SO(3)(-)-->6)GlcNAcbeta1-->3Galbeta1-->4(SO(3)(-)-->6)GlcNAc (L2L2), while lacto-N-tetraose and lacto-N-neo-tetraose were poor substrates. Moreover, we found that among the other five beta3Gn-Ts and i antigen-producing beta3Gn-T (iGn-T), beta3Gn-T2 and iGn-T act well on L2L2, although these specific activities were lower than those for a tetraantennary N-glycan. These results indicate that beta3Gn-T7 is the one that most efficiently elongates L2L2 and may be involved in the biosynthesis of keratan sulfate.
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Affiliation(s)
- Akira Seko
- Department of Biochemistry, Sasaki Institute, 2-2, Kanda-Surugadai, Chiyoda-ku, 101-0062, Tokyo, Japan
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Asano M, Nakae S, Kotani N, Shirafuji N, Nambu A, Hashimoto N, Kawashima H, Hirose M, Miyasaka M, Takasaki S, Iwakura Y. Impaired selectin-ligand biosynthesis and reduced inflammatory responses in beta-1,4-galactosyltransferase-I-deficient mice. Blood 2003; 102:1678-85. [PMID: 12714507 DOI: 10.1182/blood-2003-03-0836] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Selectins recognize ligands containing carbohydrate chains such as sialyl Lewis x (sLex) that are mainly presented at the terminus of N-acetyl lactosamine repeats on core 2 O-glycans. Several glycosyltransferases act successively to extend the N-acetyl lactosamine repeats and to synthesize sLex, and beta-1,4-galactosyltransferase (beta4GalT) plays a key role in these processes. Recently isolated 6 beta4GalT genes are candidates, but their individual roles, including those in selectin-ligand biosynthesis, remain to be elucidated. More than 80% of the core 2 O-glycans on the leukocyte membrane glycoproteins of beta4GalT-I-deficient mice lacked galactose residues in beta-1,4 linkage, and soluble P-selectin binding to neutrophils and monocytes of these mice was significantly reduced, indicating an impairment of selectin-ligand biosynthesis. beta4GalT-I-deficient mice exhibited blood leukocytosis but normal lymphocyte homing to peripheral lymph nodes. Acute and chronic inflammatory responses, including the contact hypersensitivity (CHS) and delayed-type hypersensitivity (DTH) responses, were suppressed, and neutrophil infiltration into inflammatory sites was largely reduced in these mice. Our results demonstrate that beta4GalT-I is a major galactosyltransferase responsible for selectin-ligand biosynthesis and that inflammatory responses of beta4GalT-I-deficient mice are impaired because of the defect in selectin-ligand biosynthesis.
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Affiliation(s)
- Masahide Asano
- Department of Transgenic Animal Science, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-8640, Japan.
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