Papers - Fujimoto Yukari

Total synthesis of naturally occurring chiral cyclopropane fatty acids and related compounds

Inuki S., Fujimoto Y.

Tetrahedron Letters (Tetrahedron Letters)  60 ( 16 ) 1083 - 1090 2019.04

ISSN  00404039

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© 2019 Elsevier Ltd Cyclopropane fatty acids (CFAs) and related compounds containing CFAs commonly occur in various natural sources, including plants or microorganisms. Some CFAs exhibit intriguing biological activities such as antifungal or immunosuppressive activities. Due to their biological importance and structural features, a number of synthetic studies have been conducted to date. These total syntheses have helped to elucidate their structural determinants or biological activities. Herein the total syntheses of naturally occurring CFAs and related compounds are summarized.

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Structure-activity relationship studies of Bz amide-containing α-GalCer derivatives as natural killer T cell modulators

Kishi J., Inuki S., Hirata N., Kashiwabara E., Yoshidome D., Ichihara O., Fujimoto Y.

Bioorganic and Medicinal Chemistry Letters (Bioorganic and Medicinal Chemistry Letters)  29 ( 8 ) 970 - 973 2019.04

ISSN  0960894X

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© 2019 Elsevier Ltd CD1d is a non-polymorphic antigen-presenting glycoprotein that recognizes glycolipids as ligands. Ligands bind to the hydrophobic grooves of CD1d, and the resulting ligand-CD1d complexes activate natural killer T (NKT) cells by means of T cell receptor recognition, leading to the secretion of various cytokines. However, details of the ligand recognition mechanism of a large hydrophobic ligand binding pocket and the relationship between cytokine induction and ligand structure are unclear. We report the synthesis of α-GalCer derivatives containing a Bz amide group having various substituting groups in the ceramide moiety, and the analysis of the structure-activity relationships. The assays reveal that the Bz amide-containing CD1d ligands function as NKT cell modulators displaying Th2 cytokine biasing responses. Furthermore, molecular dynamics simulation studies suggest that the phenyl groups can interact with the aromatic amino acid residues in the lipid binding pocket of CD1d.

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Glycans in infection and immunity

Suzuki T., Okamatsu M., Sakoda Y., Kinoshita T., Katayama T., Kiyono H., Goto Y., Takegawa K., Yokoyama N., Fujimoto Y., Angata T., Ohtani K., Wakamiya N., Arase H., Nishihara S., Suda Y.

Glycoscience: Basic Science to Applications: Insights from the Japan Consortium for Glycobiology and Glycotechnology (JCGG) (Glycoscience: Basic Science to Applications: Insights from the Japan Consortium for Glycobiology and Glycotechnology (JCGG))     227 - 257 2019.01

ISSN  9789811358555

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Synthesis of glycerolipids containing simple linear acyl chains or aromatic rings and evaluation of their Mincle signaling activity

Matsumaru T., Ikeno R., Shuchi Y., Iwamatsu T., Tadokoro T., Yamasaki S., Fujimoto Y., Furukawa A., Maenaka K.

Chemical Communications (Chemical Communications)  55 ( 5 ) 711 - 714 2019

ISSN  13597345

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© The Royal Society of Chemistry. Mincle, expressed in activated phagocytes, recognizes the lipid ligand to activate the innate immune system. We have synthesized glycerol derivatives possessing simple alkyl chains or aromatic rings and elucidated their structure-activity relationships using a Mincle-mediated signaling assay. The activity depends on the length of the simple acyl chains of the glycerol derivatives.

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Potent Th2 Cytokine-Bias of Natural Killer T Cell by CD1d Glycolipid Ligands Based on “Anchoring Effect” of Polar Groups in Their Lipid Component.

Inuki, S., Kashiwabara, E., Hirata, N., Kishi, J., Nabika, E., Fujimoto, Y.

Angew. Chem. Int. Ed. 57 ( 31 ) 9655 - 9659 2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  14337851

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© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Th2-biasing CD1d ligands are attractive potential candidates for adjuvants and therapeutic drugs. However, the number of potent ligands is limited, and their biasing mechanism remain unclear. Herein, a series of novel Th2-biasing CD1d glycolipid ligands, based on modification of their lipid part, have been identified. These have shown high binding affinities and efficient Th2 cytokine production. Importantly, the truncated acyl chain containing variants still retain their binding affinities and agonistic activities, which can be associated with an “anchoring effect,” that is, formation of a buried hydrogen bond between a polar group on the acyl chain and the CD1d lipid-binding pocket. The analysis indicated that the appearance rates of ligand–CD1d complexes on the cell surface were involved in Th2-biasing responses. The designed ligands, having the anchor in the shorter lipid part, are one of the most potent Th2-biasing ligands among the known ligands.

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Lymphoid tissue-resident Alcaligenes LPS induces IgA production without excessive inflammatory responses via weak TLR4 agonist activity.

Shibata, N., Kunisawa, J., Hosomi, K., Fujimoto, Y., Mizote, K., Kitayama, N., Shimoyama, A., Mimuro, H., Sato, S., Kishishita, N., Ishii, K. J., Fukase, K., Kiyono, H.

Mucosal Immunol. (Mucosal Immunology)  11 ( 3 ) 693 - 702 2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  19330219

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© The Author(s) 2018. Alcaligenes are opportunistic commensal bacteria that reside in gut-associated lymphoid tissues such as Peyer's patches (PPs); however, how they create and maintain their homeostatic environment, without inducing an excessive inflammatory response remained unclear. We show here that Alcaligenes-derived lipopolysaccharide (Alcaligenes LPS) acts as a weak agonist of toll-like receptor 4 and promotes IL-6 production from dendritic cells, which consequently enhances IgA production. The inflammatory activity of Alcaligenes LPS was weaker than that of Escherichia coli-derived LPS and therefore no excessive inflammation was induced by Alcaligenes LPS in vitro or in vivo. Alcaligenes LPS also showed adjuvanticity, inducing antigen-specific immune responses without excessive inflammation. These findings reveal the presence of commensal bacteria-mediated homeostatic inflammatory conditions within PPs that produce optimal IgA induction without causing pathogenic inflammation and suggest that Alcaligenes LPS could be a safe and potent adjuvant.

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Site-specific effect of polar functional group-modification in lipids of TLR2 ligands for modulating the ligand immunostimulatory activity.

Arai, Y., Inuki, S., Fujimoto, Y.

Bioorg Med Chem Lett. (Bioorganic and Medicinal Chemistry Letters)  28 ( 9 ) 1638 - 1641 2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0960894X

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© 2018 Elsevier Ltd Toll-like receptor 2 (TLR2), a member of the TLR innate immune receptor family, recognizes lipoproteins from bacteria and modulates the immune response by inducing the expression of various cytokines. TLR2 has a large hydrophobic pocket that recognizes long fatty acyl groups on TLR2 ligands. However, few studies have focused on the property of the hydrophobic TLR2 pocket. Based on the X-ray crystal structure of TLR2, small polar regions were found in the hydrophobic TLR2 pocket. Interactions between the polar residues and ligands were explored here by designing and synthesizing a Pam2CSK4 derivative of the TLR2 ligands, containing an amide group within the lipid moiety. We evaluated the binding affinities and immunomodulatory activities of these ligands. Results suggested that the amide groups in the lipid chain interacted with the polar residues in the hydrophobic lipid-binding pocket of TLR2.

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Time-lapse monitoring of TLR2 ligand internalization with newly developed fluorescent probes.

Arai, Y., Yokoyama, K., Kawahara, Y., Feng, Q., Ohta, I., Shimoyama, A., Inuki, S., Fukase, K., Kabayama, K., Fujimoto, Y.

Org. Biomol. Chem. (Organic and Biomolecular Chemistry)  16 ( 20 ) 3824 - 3830 2018

Research paper (scientific journal), Joint Work,  ISSN  14770520

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© 2018 The Royal Society of Chemistry. As a mammalian toll-like receptor family member protein, TLR2 recognizes lipoproteins from bacteria and modulates the immune response by inducing the expression of various cytokines. We have developed fluorescence-labeled TLR2 ligands with either hydrophilic or hydrophobic fluorescence groups. The labeled ligands maintained the inflammatory IL-6 induction activity and enabled us to observe the internalization and colocalization of the TLR2 ligands using live-cell imaging. The time-lapse monitoring in the live-cell imaging of the fluorescence-labeled TLR2 ligand showed that TLR2/CD14 expression in the host cells enhanced the internalization of TLR2 ligand molecules.

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The second and third amino acids of Pam2 lipopeptides key for the proliferation of cytotoxic T cells.

Takeda, Y., Azuma, M., Hatsugai, R., Fujimoto, Y., Hashimoto, M., Fukase, K., Matsumoto, M., Seya, T.

Innate Immunity (Innate Immunity)  24 ( 5 ) 323 - 331 2018

Research paper (scientific journal), Joint Work,  ISSN  17534259

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© The Author(s) 2018. The TLR2 agonist, dipalmitoyl lipopeptide (Pam2LP), has been used as an immune adjuvant without much success. Pam2LP is recognised by TLR2/6 receptors in humans and in mice. This study examined the proliferative activity of cytotoxic T lymphocytes (CTL) using mouse Ag-presenting dendritic cells (DCs) and OT-I assay system, where a library of synthetic Pam2LP was utilised from the Staphylococcus aureus database. Ag-specific CTL expansion and IFN-γ levels largely depended on the Pam2LP peptide sequence. The first Aa is cysteine (Cys), which has an active SH residue to bridge fatty acids, and the second and third Aa are hydrophilic or non-polar. The sequence structurally adapted to the residual constitution of the reported TLR2/6 pocket. The inactive sequence contained proline or leucine/isoleucine after the first Cys. Notably, no direct activation of OT-I cells was detected without DCs by stimulation with the active Pam2LP having the Cys-Ser sequence. MyD88, but not TICAM-1 or IFN pathways, in DCs participates in DC maturation characterised by upregulation of CD40, CD80 and CD86. Hence, the active Pam2LPs appear suitable for dimeric TLR2/6 on DCs, resulting in induction of DC maturation.

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Synthesis of Cyclopropane Fatty Acids by C(sp3)–C(sp3) Cross-coupling Reaction and Formal Synthesis of α-Mycolic Acid.

Iwasaki, T., Terahigashi, S., Wang, Y., Tanaka, A., Zhao, H., Fujimoto, Y., Fukase, K., Kambe. N.

Adv. Synth. Catal. (Advanced Synthesis and Catalysis)  in press ( 19 ) 3810 - 3817 2018

Research paper (scientific journal), Joint Work,  ISSN  16154150

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© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim An iterative Ni-catalyzed C(sp3)−C(sp3) cross-coupling reaction of a novel cis-cyclopropane containing bifunctional building blocks with alkyl halides and alkyl Grignard reagents enabled the introduction of a cyclopropane ring into the desired position(s) of saturated carbon frameworks, providing a straightforward synthetic route to cyclopropane fatty acids. The present method creates a direct route for the construction of saturated carbon frameworks, and can avoid the tedious multistep operations based on unsaturated functional group manipulations that are often employed in conventional synthetic routes. This method could be applicable to the synthesis of trans-cyclopropane fatty acids and enantioenriched cyclopropane fatty acids. Formal synthesis of α-mycolic acid was achieved by the C(sp3)−C(sp3) cross-coupling reaction of cyclopropane-containing bifunctional building blocks. (Figure presented.).

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Syntheses and Immunological Evaluation of Self-Adjuvanting Clustered N-Acetyl and N-Propionyl Sialyl-Tn Combined with A T-helper Cell Epitope as Antitumor Vaccine Candidates.

Chang, T. C., Manabe, Y., Fujimoto, Y., Ohshima, S., Kametani, Y., Kabayama, K., Nimura, Y., Lin, C. C., Fukase, K.

Angew. Chem. Int. Ed. (Angewandte Chemie - International Edition)  57 ( 27 ) 8219 - 8224 2018

Research paper (scientific journal), Joint Work,  ISSN  14337851

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© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Sialyl-Tn (STn) is a tumor-associated carbohydrate antigen (TACA) rarely observed on healthy tissues. We synthesized two fully synthetic N-acetyl and N-propionyl STn trimer (triSTn) vaccines possessing a T-helper epitope and a TLR2 agonist, since the clustered STn antigens are highly expressed on many cancer cells. Immunization of both vaccines in mice induced the anti-triSTn IgG antibodies, which recognized triSTn-expressing cell lines PANC-1 and HepG2. The N-propionyl triSTn vaccine induced the triSTn-specific IgGs, while IgGs induced by the N-acetyl triSTn vaccine were less specific. These results illustrated that N-propionyl triSTn is a valuable unnatural TACA for anticancer vaccines.

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Employing BINOL-phosphoroselenoyl chloride for selective inositol phosphorylation and chemical synthesis of glycosyl inositol phospholipid from Entamoeba histolytica.

Aiba, T., Suehara, S., Choy, S.-L., Maekawa, Y., Lotter, H., Murai, T., Inuki, S., Fukase, K., Fujimoto, Y.

Chem. Eur. J. 23   8304 - 8308 2017.04

Research paper (scientific journal), Joint Work, Accepted

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Formal Total Synthesis of L-Ossamine via Decarboxylative Functionalization Using Visible-Light-Mediated Photoredox Catalysisin a Flow System

Inuki, S., Sato, K., Fukuyama, T., Ryu, I., Fujimoto, Y.

J. Org. Chem. 82 ( 2 ) 1248 - 1253 2017.01

Research paper (scientific journal), Accepted

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Synthesis of Peptidoglycan Fragments from Enterococcus faecalis with Fmoc-Strategy for Glycan Elongation.

Wang, N., Hasegawa, H., Huang, CY., Fukase, K., Fujimoto, Y.

Chem Asian J. 12 ( 1 ) 27 - 30 2017.01

Research paper (scientific journal)

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Convergent Synthesis of Digalactosyl Diacylglycerols.

Inuki, S., Kishi, J., Kashiwabara, E., Aiba, T., Fujimoto, Y.

Org. Lett. 19   6482 2017

Research paper (scientific journal), Joint Work, Accepted

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Funiculosin variants and phosphorylated derivatives promote innate immune responses via the Toll-like receptor 4/myeloid differentiation factor-2 complex.

Okamoto, N., Mizote, K., Honda, H., Saeki, A., Watanabe, Y., Yamaguchi-Miyamoto, T., Fukui, R., Tanimura, N., Motoi, Y., Akashi-Takamura, S., Kato, T., Fujishita, S., Kimura, T., Ohto, U., Shimizu, T., Hirokawa, T., Miyake, K., Fukase, K.,Fujimoto, Y., Nagai, Y., Takatsu, K.

J. Biol. Chem. 292 ( 37 ) 15378 - 15394 2017

Research paper (scientific journal), Joint Work, Accepted

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A Comprehensive Study of the Interaction between Peptidoglycan Fragments and the Extracellular Domain of Mycobacterium tuberculosis Ser/Thr Kinase PknB.

Wang, Q., Marchetti, R., Prisic, S., Ishii, K., Arai, Y., Ohta, I., Inuki, S., Uchiyama, S., Silipo, A., Molinaro, A., Husson, R. N., Fukase, K.,. Fujimoto, Y.

ChemBioChem 18   2094 - 2098 2017

Research paper (scientific journal), Joint Work, Accepted

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Chemical Synthesis of D-glycero-D-manno-Heptose 1,7-Bisphosphate and Evaluation of Its Ability to Modulate NF-κB Activation.

Inuki, S., Aiba, T., Kawakami, S., Akiyama, T., Inoue, J. I., Fujimoto, Y.

Org. Lett. 19 ( 12 ) 3079 - 3082 2017

Research paper (scientific journal), Joint Work, Accepted

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Total Synthesis of Cardiolipins Containing Chiral Cyclopropane Fatty Acids.

Inuki, S., Ohta, I., Ishibashi, S., Takamatsu, M., Fukase, K., Fujimoto, Y.

J. Org. Chem. 82 ( 15 ) 7832 - 7838 2017

Research paper (scientific journal), Joint Work, Accepted

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Synthetic analogs of a protozoan glycolipid designed to combat intracellular Leishmania infection.

Choy, S. L., Bernin, H., Aiba, T., Bifeld, E., Lender, S. C., Mühlenpfordt, M., Noll, J., Eick, J., Marggraff, C., Niss, H., Roldán, N. G., Tanaka, S., Kitamura, M., Fukase, K., Clos, J., Tannich, E., Fujimoto, Y., Lotter, H.

Sci. Rep. 7   9472 2017

Research paper (scientific journal), Joint Work, Accepted

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