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Ohmi Y, Nishikaze T, Kitaura Y, Ito T, Yamamoto S, Sugiyama F, Matsuyama M, Takahashi Y, Takeda A, Kawahara T, Okajima T, Furukawa K, Furukawa K. Majority of alpha2,6-sialylated glycans in the adult mouse brain exist in O-glycans: SALSA-MS analysis for knockout mice of alpha2,6-sialyltransferase genes. Glycobiology 2020; 31:557-570. [PMID: 33242079 DOI: 10.1093/glycob/cwaa105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 10/14/2020] [Accepted: 10/26/2020] [Indexed: 11/13/2022] Open
Abstract
Sialic acids are unique sugars with negative charge and exert various biological functions such as regulation of immune systems, maintenance of nerve tissues and expression of malignant properties of cancers. Alpha 2,6 sialylated N-glycans, one of representative sialylation forms, are synthesized by St6gal1 or St6gal2 gene products in humans and mice. Previously, it has been reported that St6gal1 gene is ubiquitously expressed in almost all tissues. On the other hand, St6gal2 gene is expressed mainly in the embryonic and perinatal stages of brain tissues. However, roles of St6gal2 gene have not been clarified. Expression profiles of N-glycans with terminal α2,6 sialic acid generated by St6gal gene products in the brain have never been directly studied. Using conventional lectin blotting and novel sialic acid linkage-specific alkylamidationmass spectrometry method (SALSA-MS), we investigated the function and expression of St6gal genes and profiles of their products in the adult mouse brain by establishing KO mice lacking St6gal1 gene, St6gal2 gene, or both of them (double knockout). Consequently, α2,6-sialylated N-glycans were scarcely detected in adult mouse brain tissues, and a majority of α2,6-sialylated glycans found in the mouse brain were O-linked glycans. The majority of these α2,6-sialylated O-glycans were shown to be disialyl-T antigen and sialyl-(6)T antigen by mass spectrometry analysis. Moreover, it was revealed that a few α2,6-sialylated N-glycans were produced by the action of St6gal1 gene, despite both St6gal1 and St6gal2 genes being expressed in the adult mouse brain. In the future, where and how sialylated O-linked glycoproteins function in the brain tissue remains to be clarified.
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Affiliation(s)
- Yuhsuke Ohmi
- Department of Clinical Engineering, Chubu University College of Life and Health Sciences, Kasugai, Aichi 487-8501, Japan
| | - Takashi Nishikaze
- Koichi Tanaka Mass Spectrometry Research Laboratory, Shimadzu Corporation, 1, Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto 604-8511, Japan
| | - Yoko Kitaura
- Department of Clinical Engineering, Chubu University College of Life and Health Sciences, Kasugai, Aichi 487-8501, Japan
| | - Takako Ito
- Department of Clinical Engineering, Chubu University College of Life and Health Sciences, Kasugai, Aichi 487-8501, Japan
| | - Satoko Yamamoto
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Aichi 487-8501, Japan
| | - Fumihiro Sugiyama
- Laboratory Animal Resource Center, University of Tsukuba, Tsukuba 305-8575, Japan
| | - Makoto Matsuyama
- Division of Molecular Genetics, Shigei Medical Research Institute, 2117, Yamada, Minami-ku, Okayama 701-0202, Japan
| | - Yoshimasa Takahashi
- Department of Immunology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Akira Takeda
- Department of Clinical Engineering, Chubu University College of Life and Health Sciences, Kasugai, Aichi 487-8501, Japan
| | - Toshio Kawahara
- Department of Clinical Engineering, Chubu University College of Life and Health Sciences, Kasugai, Aichi 487-8501, Japan
| | - Tetsuya Okajima
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, Nagoya 466-0065, Japan
| | - Keiko Furukawa
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Aichi 487-8501, Japan
| | - Koichi Furukawa
- Department of Biomedical Sciences, Chubu University College of Life and Health Sciences, Kasugai, Aichi 487-8501, Japan.,Department of Biochemistry II, Nagoya University Graduate School of Medicine, Nagoya 466-0065, Japan
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Bradford BM, Crocker PR, Mabbott NA. Peripheral prion disease pathogenesis is unaltered in the absence of sialoadhesin (Siglec-1/CD169). Immunology 2014; 143:120-9. [PMID: 24684244 PMCID: PMC4137961 DOI: 10.1111/imm.12294] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 03/18/2014] [Accepted: 03/24/2014] [Indexed: 01/09/2023] Open
Abstract
Prions are a unique group of pathogens, which are considered to comprise solely of an abnormally folded isoform of the cellular prion protein. The accumulation and replication of prions within secondary lymphoid organs is important for their efficient spread from the periphery to the brain where they ultimately cause neurodegeneration and death. Mononuclear phagocytes (MNP) play key roles in prion disease pathogenesis. Some MNP appear to facilitate the propagation of prions to and within lymphoid tissues, whereas others may aid their clearance by phagocytosis and by destroying them. Our recent data show that an intact splenic marginal zone is important for the efficient delivery of prions into the B-cell follicles where they subsequently replicate upon follicular dendritic cells before infecting the nervous system. Sialoadhesin is an MNP-restricted cell adhesion molecule that binds sialylated glycoproteins. Sialoadhesin is constitutively expressed upon splenic marginal zone metallophilic and lymph node sub-capsular sinus macrophage populations, where it may function to bind sialylated glycoproteins, pathogens and exosomes in the blood and lymph via recognition of terminal sialic acid residues. As the prion glycoprotein is highly sialylated, we tested the hypothesis that sialoadhesin may influence prion disease pathogenesis. We show that after peripheral exposure, prion pathogenesis was unaltered in sialoadhesin-deficient mice; revealing that lymphoid sequestration of prions is not mediated via sialoadhesin. Hence, although an intact marginal zone is important for the efficient uptake and delivery of prions into the B-cell follicles of the spleen, this is not influenced by sialoadhesin expression by the MNP within it.
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Affiliation(s)
- Barry M Bradford
- The Roslin Institute and R(D)SVS, University of EdinburghMidlothian, UK
| | - Paul R Crocker
- College of Life Sciences, University of DundeeDundee, UK
| | - Neil A Mabbott
- The Roslin Institute and R(D)SVS, University of EdinburghMidlothian, UK,Correspondence: Dr Neil A. Mabbott, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK., , Senior author: Neil A. Mabbott
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