研究者詳細 - 佐藤　ちひろ

Chemical Synthesis and Evaluation of a Disialic Acid-Containing Dextran Polymer as an Inhibitor for the Interaction between Siglec 7 and Its Ligand. Open Access

Yamaguchi S, Yoshimura A, Yasuda Y, Mori A, Tanaka H, Takahashi T, Kitajima K, Sato C

Chembiochem : a European journal of chemical biology 18 巻 ( 13 ) 頁： 1194 - 1203 2017年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chembiochem

A new sialic acid (Sia)-containing glycopolymer—a fluorescent probe with high-density disialic acid (diSia) on the surface of polysaccharide dextran (diSia-Dex)—was synthesized as a key molecule to regulate the Sia recognition lectins, Siglecs, that are involved in the immune system. According to our original methods, diSia was synthesized by α-selective sialylation, and a dextran template possessing terminal acetylenes and amino groups was prepared. A diSia and a fluorescent molecule were subsequently introduced to surface-modified dextran by Hüisgen reaction and amidation, respectively. The modulatory activity of Siglec7 was evaluated by using synthetic probes. DiSia-Dex showed high binding avidity toward Siglec7, with a K<inf>D</inf> value of 5.87×10<sup>−10</sup> m, and a high inhibitory activity for the interaction between Siglec7 and a ligand (GD3), with a IC<inf>50</inf> value of 1.0 nm. Notably, diSia-Dex was able to release Siglec7 from the pre-existing Siglec7–GD3 complex, possibly due to its unique properties of a slow dissociation rate and a high association rate. Together, these data show that diSia-Dex can be widely applicable as a modulator of Siglec7 functions.

DOI： 10.1002/cbic.201600694

Alpha-2 macroglobulin as a region-specific secretory protein in male reproductive tract, and its dynamics during sperm transit toward the female spermatheca in the blue crab. Open Access

Senarai T, Vanichviriyakit R, Miyata S, Sato C, Sretarugsa P, Weerachatyanukul W, Kitajima K

Molecular reproduction and development 84 巻 ( 7 ) 頁： 585 - 595 2017年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Molecular Reproduction and Development

A 250-kDa protein was isolated from fluid in the middle spermatic duct (MSD) of the blue crab (Portunus pelagicus). N-terminal and partial amino acid sequences revealed that this MSD-specific protein is highly similar to the plasma-enriched protein Alpha-2 macroglobulin (α2M). The P. pelagicus ortholog (Ppα2M) is a large glycoprotein possessing mannose and N-acetylglucosamine residues. Ppa2m mRNA was detected in the spermatic duct, androgenic gland, and hematopoietic tissue, whereas the protein was primarily observed in the apical cytoplasm of MSD epithelium and in the matrix of the acrosome of MSD sperm; distally within spermatic duct, Ppα2M was lost from the sperm membrane but remained in the sperm acrosome. These results suggest that Ppα2M is expressed and glycosylated in the epithelium of spermatic ducts, secreted into MSD fluid, taken up by sperm in the MSD, and removed from the surface of sperm during its transit towards the female spermatheca. Given that Ppα2M also exhibits protease inhibitor activity, we hypothesize that acrosome localized Ppα2M may suppress premature acrosome reaction during post-testicular sperm maturation in this crab.

DOI： 10.1002/mrd.22817

Chlorpromazine Increases the Expression of Polysialic Acid (PolySia) in Human Neuroblastoma Cells and Mouse Prefrontal Cortex. Open Access

Abe C, Nishimura S, Mori A, Niimi Y, Yang Y, Hane M, Kitajima K, Sato C

International journal of molecular sciences 18 巻 ( 6 ) 頁： 1123 2017年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Molecular Sciences

The neural cell adhesion molecule (NCAM) is modified by polysialic acid (polySia or PSA) in embryonic brains. In adult brains, polySia modification of NCAM is only observed in restricted areas where neural plasticity, remodeling of neural connections, or neural generation is ongoing although the amount of NCAM remains unchanged. Impairments of the polySia-expression and several single nucleotide polymorphisms (SNPs) of the polysialyltransferase (polyST) ST8SIA2 gene are reported to be associated with schizophrenia and bipolar disorder. Chlorpromazine (CPZ) is well-known as an agent for treating schizophrenia, and our hypothesis is that CPZ may affect the polySia expression or the gene expression of polySTs or NCAM. To test this hypothesis, we analyzed the effects of CPZ on the expression of polySia-NCAM on human neuroblastoma cell line, IMR-32 cells, by immunochemical and chemical methods. Interestingly, the cell surface expression of polySia, especially those with lower chain lengths, was significantly increased on the CPZ-treated cells, while mRNAs for polySTs and NCAM, and the amounts of total polySia-NCAM remained unchanged. The addition of brefeldin A, an inhibitor of endocytosis, suppressed the CPZ-induced cell surface polySia expression. In addition, polySia-NCAM was also observed in the vesicle compartment inside the cell. All these data suggest that the level of cell surface expression of polySia in IMR-32 is highly regulated and that CPZ changes the rate of the recycling of polySia-NCAM, leading to the up-regulation of polySia-NCAM on the cell surface. We also analyzed the effect of CPZ on polySia-expression in various brain regions in adult mice and found that CPZ only influenced the total amounts of polySia-NCAM in prefrontal cortex. These results suggest a brain-region-specific effect of CPZ on the expression of total polySia in mouse brain. Collectively, anti-schizophrenia agent CPZ consistently up-regulates the expression polySia at both cellular and animal levels.

DOI： 10.3390/ijms18061123

Altered expression of ganglioside GM3 molecular species and a potential regulatory role during myoblast differentiation. Open Access

Go S, Go S, Veillon L, Ciampa MG, Mauri L, Sato C, Kitajima K, Prinetti A, Sonnino S, Inokuchi JI

The Journal of biological chemistry 292 巻 ( 17 ) 頁： 7040 - 7051 2017年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Biological Chemistry

Gangliosides (sialic acid-containing glycosphingolipids) help regulate many important biological processes, including cell proliferation, signal transduction, and differentiation, via formation of functional microdomains in plasma membranes. The structural diversity of gangliosides arises from both the ceramide moiety and glycan portion. Recently, differing molecular species of a given ganglioside are suggested to have distinct biological properties and regulate specific and distinct biological events. Elucidation of the function of each molecular species is important and will provide new insights into ganglioside biology. Gangliosides are also suggested to be involved in skeletal muscle differentiation; however, the differential roles of ganglioside molecular species remain unclear. Here we describe striking changes in quantity and quality of gangliosides (particularly GM3)during differentiation of mouse C2C12 myoblast cells and key roles played by distinct GM3 molecular species at each step of the process.

DOI： 10.1074/jbc.M116.771253

Diverse subcellular localizations of the insect CMP-sialic acid synthetases. Open Access

Di W, Fujita A, Hamaguchi K, Delannoy P, Sato C, Kitajima K

Glycobiology 27 巻 ( 4 ) 頁： 329 - 341 2017年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Glycobiology

The occurrence and biological importance of sialic acid (Sia) and its metabolic enzymes in insects have been studied using Drosophila melanogaster. The most prominent feature of D. melanogaster CMP-Sia synthetase (DmCSS) is its Golgi-localization, contrasted with nuclear localization of vertebrate CSSs. However, it remains unclear if the Golgi-localization is common to other insect CSSs and why it happens. To answer these questions, Aedes aegypti (mosquito) CSS (AaCSS) and Tribolium castaneum (beetle) CSS (TcCSS) were cloned and characterized for their activity and subcellular localization. Our new findings show: (1) AaCSS and TcCSS share a common overall structure with DmCSS in terms of evolutionarily conserved motifs and the absence of the C-terminal domain typical to vertebrate CSSs; (2) when expressed in mammalian and insect cells, AaCSS and TcCSS showed in vivo and in vitro CSS activities, similar to DmCSS. In contrast, when expressed in bacteria, they lacked CSS activity because the N-terminal hydrophobic region appeared to induce protein aggregation; (3) when expressed in Drosophila S2 cells, AaCSS and TcCSS were predominantly localized in the ER, but not in the Golgi. Surprisingly, DmCSS was mainly secreted into the culture medium, although partially detected in Golgi. Consistent with these results, the N-terminal hydrophobic regions of AaCSS and TcCSS functioned as a signal peptide to render them soluble in the ER, while the N-terminus of DmCSS functioned as a membrane-spanning region of type II transmembrane proteins whose cytosolic KLK sequence functioned as an ER export signal. Accordingly, the differential subcellular localization of insect CSSs are distinctively more diverse than previously recognized.

DOI： 10.1093/glycob/cww128

Synthesis of end-functionalized glycopolymers containing α(2,8) disialic acids via π-allyl nickel catalyzed coordinating polymerization and their interaction with Siglec-7. 査読有り

Ohira S, Yasuda Y, Tomita I, Kitajima K, Takahashi T, Sato C, Tanaka H

Chemical communications (Cambridge, England) 53 巻 ( 3 ) 頁： 553 - 556 2017年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemical Communications

An allene monomer containing an α(2,8) disialic acid was polymerized by a π-allyl nickel complex with an azido group to produce end-functional glycopolymers with an excellent polydispersity index. The polymers allowed terminal modification with a fluorescent dye by click chemistry. The glycopolymers can dissociate Siglec-7-GD3 interactions at low concentrations.

DOI： 10.1039/c6cc07115e

Synthesis of end-functionalized glycopolymers containing α(2,8) disialic acids via π-allyl nickel catalyzed coordinating polymerization and their interaction with Siglec-7. 査読有り

Ohira S, Yasuda Y, Tomita I, Kitajima K, Takahashi T, Sato C, Tanaka H.

Chem Commun (Camb). 53 巻 ( 3 ) 頁： 553-556. 2017年1月

Releasing Mechanism of Neurotrophic Factors via Polysialic Acid.

Sato C

Vitamins and hormones 104 巻頁： 89 - 112 2017年

記述言語：英語掲載種別：論文集(書籍)内論文出版者・発行元：Vitamins and Hormones

Neurotrophins are well-characterized neurologically active molecules in the central nervous system. The regulation of these signaling molecules, which are involved in cell growth, differentiation, and survival, is critical for normal brain function. Among the different types of neurotrophins, brain-derived neurotrophic factor (BDNF) is involved in various brain functions, including memory consolidation, synaptic plasticity, and adult neurogenesis, and is therefore a key molecule for understanding comprehensive brain function and neurodevelopmental and psychiatric diseases. The concentration of BDNF in body fluid is highly related to several neurodevelopmental and psychiatric diseases, including Alzheimer's diseases, depression, schizophrenia, and bipolar disorder. In the present review, the mechanisms by which BDNF is released from secretory vesicles are reviewed, with a particular focus on the recently described glycan-mediated release. In addition, the impact of glycan-mediated BDNF release on psychiatric disorders is also discussed.

DOI： 10.1016/bs.vh.2016.11.004

Effects of intronic single nucleotide polymorphisms (iSNPs) of a polysialyltransferase, ST8SIA2 gene found in psychiatric disorders on its gene products. 査読有り

ポリシアル酸転移酵素遺伝子ST8SIA2と精神疾患の関わり査読有り Open Access

羽根正弥, 北島健, 佐藤ちひろ

生化学 89 巻頁： 634 - 643 2017年

Diverse subcellular localizations of the insect CMP-sialic acid synthetases. 査読有り Open Access

Di W, Fujita A, Hamaguchi K, Delannoy P, Sato C, Kitajima K.

Glycobiology. 2016年12月

Hane M, Kitajima K, Sato C

Biochemical and biophysical research communications 478 巻 ( 3 ) 頁： 1123 - 9 2016年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Biochemical and Biophysical Research Communications

Polysialic acid (polySia) is a linear homopolymer of sialic acid and mainly modifies neural cell adhesion molecule. PolySia plays important roles in synapse formation, learning and memory, social behavior and is associated with several diseases. Gene analyses of one of the biosynthetic enzymes for polySia, ST8SIA2, have revealed that several SNPs and genetic variations in the ST8SIA2 gene are associated with several psychiatric disorders; however, the mechanisms underlying these associations remain unknown. Here, we analyzed the effects of two iSNPs of ST8SIA2, rs2168351 and rs3784730, which are associated with bipolar disorder and autism spectrum disorder, respectively, on the expression of mRNA, ST8SIA2 and its final product, polySia in mouse neuroblastoma and human adenocarcinoma cell lines. We found that both iSNPs affected the expression of pre-mRNA and mRNA of ST8SIA2, and altered the cellular levels of ST8SIA2 and polySia. Taken together, these results indicate that impairment of the regulated expression of ST8SIA2 and the resulting downstream effects on gene products by these two iSNPs contribute to the development of these psychiatric disorders.

DOI： 10.1016/j.bbrc.2016.08.079

Relationship between ST8SIA2, polysialic acid and its binding molecules, and psychiatric disorders

Effects of intronic single nucleotide polymorphisms (iSNPs) of a polysialyltransferase, ST8SIA2 gene found in psychiatric disorders on its gene products. 査読有り

Hane M, Kitajima K, Sato C.

Biochem Biophys Res Commun. 478 巻 ( 3 ) 頁： 1123-9. 2016年9月

Sato C.

Biochimica et Biophysica Acta - General Subjects 1860 巻 ( 8 ) 頁： 1739 - 1752 2016年8月

Relationship between ST8SIA2, polysialic acid and its binding molecules, and psychiatric disorders. 招待有り査読有り

Sato C, Hane M, Kitajima K.

Biochim Biophys Acta. 1860 巻 ( 8 ) 頁： 1739-52 2016年8月

Relationship between ST8SIA2, polysialic acid and its binding molecules, and psychiatric disorders.

Sato C, Hane M, Kitajima K

Biochimica et biophysica acta 1860 巻 ( 8 ) 頁： 1739 - 52 2016年8月

Relationship between ST8SIA2, polysialic acid and its binding molecules, and psychiatric disorders. 査読有り

Sato C, Hane M, Kitajima K

Biochimica et biophysica acta 1860 巻 ( 8 ) 頁： 1739 - 1752 2016年8月

Relationship between ST8SIA2, polysialic acid and its binding molecules, and psychiatric disorders 査読有り

Chihiro Sato, Masaya Hane, Ken Kitajima

BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS 1860 巻 ( 8 ) 頁： 1739 - 1752 2016年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Polysialic acid (polySia, PSA) is a unique and functionally important glycan, particularly in vertebrate brains. It is involved in higher brain functions such as learning, memory, and social behaviors. Recently, an association between several genetic variations and single nucleotide polymorphisms (SNPs) of ST8SIA2/STX, one of two polysialyltransferase genes in vertebrates, and psychiatric disorders, such as schizophrenia (SZ), bipolar disorder (BD), and autism spectrum disorder (ASD), was reported based on candidate gene approaches and genome-wide studies among normal and mental disorder patients. It is of critical importance to determine if the reported mutations and SNPs in ST8SIA2 lead to impairments of the structure and function of polySia, which is the final product of ST8SIA2. To date, however, only a few such forward-directed studies have been conducted. In addition, the molecular mechanisms underlying polySia-involved brain functions remain unknown, although polySia was shown to have an anti-adhesive effect. In this report, we review the relationships between psychiatric disorders and polySia and/or ST8SIA2, and describe a new function of polySia as a regulator of neurologically active molecules, such as brain-derived neurotrophic factor (BDNF) and dopamine, which are deeply involved in psychiatric disorders. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.bbagen.2016.04.015