Synthesis of C-Glycosyl Amino Acid Building Blocks Suitable for the Solid-Phase Synthesis of Multivalent Glycopeptide Mimics

Five C-glycosyl functionalized lysine building blocks, featuring C-glycosidic derivatives of alpha-rhamnose, alpha-mannose, alpha-galactose, beta-galactose, and beta-N-acetyl glucosamine have been designed and synthesized. These derivatives, equipped with acid-labile protecting groups, are eminently suitable for solid-phase synthesis of multivalent glycopeptides. The lysine building blocks were prepared fromC-allyl glycosides that underwent a Grubbs cross-metathesis with an acrylate, followed by a reduction of the C=C double bond in the resulting alpha,beta-unsaturated esters, and liberation of the carboxylate to allow condensation with a lysine side chain. The thus obtainedC-glycosides, five in total, were applied in the solid-phase peptide synthesis (SPPS) of three glycopeptides, showing the potential of the described building blocks in the assembly of well-defined mimics of homo- and heteromultivalent glycopeptides and glycoclusters.Bio-organic Synthesi

Synthesis of C

FiveC-glycosyl functionalized lysine building blocks, featuringC-glycosidic derivatives of alpha-rhamnose, alpha-mannose, alpha-galactose, beta-galactose, and beta-N-acetyl glucosamine have been designed and synthesized. These derivatives, equipped with acid-labile protecting groups, are eminently suitable for solid-phase synthesis of multivalent glycopeptides. The lysine building blocks were prepared fromC-allyl glycosides that underwent a Grubbs cross-metathesis with an acrylate, followed by a reduction of the C=C double bond in the resulting alpha,beta-unsaturated esters, and liberation of the carboxylate to allow condensation with a lysine side chain. The thus obtainedC-glycosides, five in total, were applied in the solid-phase peptide synthesis (SPPS) of three glycopeptides, showing the potential of the described building blocks in the assembly of well-defined mimics of homo- and heteromultivalent glycopeptides and glycoclusters

Synthesis of C-Glycosyl Amino Acid Building Blocks Suitable for the Solid-Phase Synthesis of Multivalent Glycopeptide Mimics

Five C-glycosyl functionalized lysine building blocks, featuring C-glycosidic derivatives of α-rhamnose, α-mannose, α-galactose, β-galactose, and β-N-acetyl glucosamine have been designed and synthesized. These derivatives, equipped with acid-labile protecting groups, are eminently suitable for solid-phase synthesis of multivalent glycopeptides. The lysine building blocks were prepared from C-allyl glycosides that underwent a Grubbs cross-metathesis with an acrylate, followed by a reduction of the C=C double bond in the resulting α,β-unsaturated esters, and liberation of the carboxylate to allow condensation with a lysine side chain. The thus obtained C-glycosides, five in total, were applied in the solid-phase peptide synthesis (SPPS) of three glycopeptides, showing the potential of the described building blocks in the assembly of well-defined mimics of homo- and heteromultivalent glycopeptides and glycoclusters

Interleukin-18 resistance in patients with obesity and type 2 diabetes mellitus.

Contains fulltext : 69672.pdf (publisher's version ) (Closed access)OBJECTIVE: Interleukin-18 (IL-18) has been recently demonstrated to improve experimental hyperphagia and insulin resistance. Paradoxically, concentrations of circulating IL-18 in obese subjects and in patients with type 2 diabetes are increased. The objective of this study is to provide an explanation for this paradox. DESIGN: We have hypothesized that cells from obese individuals or from patients with type 2 diabetes mellitus have a diminished response to stimulation with IL-18. IL-18 responsiveness was tested by stimulating blood monocytes of obese or diabetes patients with rIL-18 or microbial components. RESULTS: Obese individuals and patients with type 2 diabetes mellitus exhibit increased circulating concentrations of IL-18. More importantly, leukocytes isolated from obese or type 2 diabetes patients respond poorly after stimulation with IL-18, as reflected by defective interferon-gamma (IFN gamma) production. The defective response to IL-18 stimulation was accompanied by a 50% reduction in the expression of IL-18R alpha and beta chains. In addition, cells of patients with obesity and diabetes displayed an impaired release of IFN gamma after challenge with bacterial or fungal pathogens, which was due to defective IL-18-mediated signaling. CONCLUSION: Patients with obesity or type 2 diabetes mellitus are characterized by lower responses after stimulation with IL-18. This IL-18 resistance explains the association of obesity and diabetes with high IL-18 circulating concentrations, similar to hyperinsulinemia and hyperleptinemia. IL-18 resistance may represent an important mechanism of the increased susceptibility of these patients to a number of infections