Die Synthese von L-Fucose-Derivation als potentielle Inhibitoren und Modulatoren des GDP-#beta#-L-Fucose-Stoffwechsels

SIGLEAvailable from TIB Hannover: DW 3740 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Carbohydrate Chemistry, Chemical and Biological Approaches, Specialist Periodical Reports, vol 43, RSC

International audienc

Carbohydrate Chemistry, Chemical and Biological Approaches, Specialist Periodical Reports, vol 43, RSC

International audienc

The hydration features of carbohydrate determinants of Lewis antigens

International audienc

Schistosoma mansoni Soluble Egg Antigens Induce Expression of the Negative Regulators SOCS1 and SHP1 in Human Dendritic Cells via Interaction with the Mannose Receptor

Schistosomiasis is a common debilitating human parasitic disease in (sub)tropical areas, however, schistosome infections can also protect against a variety of inflammatory diseases. This has raised broad interest in the mechanisms by which Schistosoma modulate the immune system into an anti-inflammatory and regulatory state. Human dendritic cells (DCs) show many phenotypic changes upon contact with Schistosoma mansoni soluble egg antigens (SEA). We here show that oxidation of SEA glycans, but not heat-denaturation, abrogates the capacity of SEA to suppress both LPS-induced cytokine secretion and DC proliferation, indicating an important role of SEA glycans in these processes. Remarkably, interaction of SEA glycans with DCs results in a strongly increased expression of Suppressor Of Cytokine Signalling1 (SOCS1) and SH2-containing protein tyrosine Phosphatase-1 (SHP1), important negative regulators of TLR4 signalling. In addition, SEA induces the secretion of transforming growth factor β (TGF-β), and the surface expression of the costimulatory molecules Programmed Death Ligand-1 (PD-L1) and OX40 ligand (OX40L), which are known phenotypic markers for the capacity of DCs to polarize naïve T cells into Th2/Treg cell subsets. Inhibition of mannose receptor (MR)-mediated internalization of SEA into DCs by blocking with allyl α-D-mannoside or anti-MR antibodies, significantly reduced SOCS1 and SHP1 expression. In conclusion, we demonstrate that SEA glycans are essential for induction of enhanced SOCS1 and SHP1 levels in DCs via the MR. Our data provide novel mechanistic evidence for the potential of S. mansoni SEA glycans to modulate human DCs, which may contribute to the capacity of SEA to down-regulate inflammatory responses

Bifunctional mannoside-glucosinolate glycoconjugates as enzymatically triggered isothiocyanates and FimH ligands

International audienceGlucosinolates are sulfur-containing secondary metabolites found in plants of the Brassicale order. They are precursors of isothiocyanate species, resulting from C–S hydrolysis catalysed by the thioglucohydrolase myrosinase. We describe the synthesis of bifunctional glucosinolate–mannoside glycoconjugates combining both the structural features of a substrate of myrosinase and a ligand of the lectin FimH. We show that these glycoconjugates serve as enzyme substrates and that myrosinase can indeed hydrolyze the glucosinolate moiety with affinities (KM, Vmax) comparable to the natural substrates glucomoringin and sinigrin. This enzymatic hydrolysis of the thioglycosidic bond led to the efficient formation of an isothiocyanate which was assessed by the formation of the corresponding dithiocarbamate derivatives. Finally, we show that our synthetic bifunctional glycoconjugates also serve as FimH ligands where the glucosinolate moiety does not hamper the interaction with the lectin. Our findings set the stage for an original bioconjugation tool, allowing for myrosinase-triggered specific labelling of lectins using glucosinolate glycoconjugates as non-toxic, water soluble isothiocyanate precursors

Multivalent glycoconjugates as anti-pathogenic agents

International audienc