Search results for "Saccharides"

TGF-beta1 in liver fibrosis: an inducible transgenic mouse model to study liver fibrogenesis.

1999

Transforming growth factor-beta1 (TGF-beta1) is a powerful stimulus for collagen formation in vitro. To determine the in vivo effects of TGF-beta1 on liver fibrogenesis, we generated transgenic mice overexpressing a fusion gene [C-reactive protein (CRP)/TGF-beta1] consisting of the cDNA coding for an activated form of TGF-beta1 under the control of the regulatory elements of the inducible human CRP gene promoter. Two transgenic lines were generated with liver-specific overexpression of mature TGF-beta1. After induction of the acute phase response (15 h) with lipopolysaccharide (100 microgram ip), plasma TGF-beta1 levels reached600 ng/ml in transgenic animals, which is100 times above normal …

Dysbiosis and zonulin upregulation alter gut epithelial and vascular barriers in patients with ankylosing spondylitis

2017

BackgroundDysbiosis has been recently demonstrated in patients with ankylosing spondylitis (AS) but its implications in the modulation of intestinal immune responses have never been studied. The aim of this study was to investigate the role of ileal bacteria in modulating local and systemic immune responses in AS.MethodsIleal biopsies were obtained from 50 HLA-B27+ patients with AS and 20 normal subjects. Silver stain was used to visualise bacteria. Ileal expression of tight and adherens junction proteins was investigated by TaqMan real-time (RT)-PCR and immunohistochemistry. Serum levels of lipopolysaccharide (LPS), LPS-binding protein (LPS-BP), intestinal fatty acid-BP (iFABP) and zonulin…

Dual effect of 1-deoxymannojirimycin on the mannose uptake and on the N-glycan processing of the human colon cancer cell line HT-29.

1990

International audience; 1-Deoxymannojirimycin (dMM), a specific alpha-mannosidase I inhibitor, completely blocks the conversion of Man9-8GlcNAc2 into Man7-5-GlcNAc2 in both differentiated and undifferentiated human adenocarcinoma HT-29 cells. Besides this well known effect on N-glycan trimming, we describe here a novel effect of this inhibitor on the D-[2-3H]mannose uptake that is exclusively observed in differentiated intestinal cells, i.e. cells that display a functional apical brush border membrane. This inhibition of D-[2-3H]mannose uptake was shown to be dose-dependent and reversible. Moreover, using microsomal fractions we showed that this effect depends only on the integrity of the b…

Rat mammary-gland transferrin: nucleotide sequence, phylogenetic analysis and glycan structure

1995

The complete cDNA for rat mammary-gland transferrin (Tf) has been sequenced and also the native protein isolated from milk in order to analyse the structure of the main glycan variants present. A lactating-rat mammary-gland cDNA library in lambda gt10 was screened with a partial cDNA copy of rat liver Tf and subsequently rescreened with 5′ fragments of the longest clones. This produced a 2275 bp insert coding for an open reading frame of 695 amino acid residues. This includes a 19-amino acid signal sequence and the mature protein containing 676 amino acids and one N-glycosylation site in the C-terminal domain at residue 490. Phylogenetic analysis was carried out using 14 translated Tf nucle…

Active Site Mapping of Xylan-Deconstructing Enzymes with Arabinoxylan Oligosaccharides Produced by Automated Glycan Assembly

2017

Xylan-degrading enzymes are crucial for the deconstruction of hemicellulosic biomass, making the hydrolysis products available for various industrial applications such as the production of biofuel. To determine the substrate specificities of these enzymes, we prepared a collection of complex xylan oligosaccharides by automated glycan assembly. Seven differentially protected building blocks provided the basis for the modular assembly of 2-substituted, 3-substituted, and 2-/3-substituted arabino- and glucuronoxylan oligosaccharides. Elongation of the xylan backbone relied on iterative additions of C4-fluorenylmethoxylcarbonyl (Fmoc) protected xylose building blocks to a linker-functionalized …

Highly regioselective synthesis of a 3-O-sulfonated arabino Lewisa asparagine building block suitable for glycopeptide synthesis

2006

Using the stannylene method, the trisaccharide 2-acetamido-3-O-[6-O-benzyl-beta-D-galactopyranosyl]-4-O-[2,3,4-tri-O-benzyl-beta-D-arabinopyranosyl]-6-O-benzyl-2-deoxy-beta-D-glucopyranosyl azide was regioselectively sulfonated and, after reduction of the anomeric azide, coupled to Fmoc alpha-allyl aspartate. After Pd(0)-catalyzed deallylation, the sulfatyl Lewis(a) asparagine building block was obtained, suitable for solid-phase glycopeptide synthesis applying the fluoride labile PTMSEL linker system.

Sweet (hetero)aromatics: glycosylated templates for the construction of saccharide mimetics

2011

Mono- and diglycosylated aromatics and heteroaromatics may serve as building blocks for the construction of metabolically stable mimetics of oligosaccharides. Methods for their preparation from monosaccharidic precursors by direct C-glycosylation, dipolar cycloaddition or Larock cyclization are described.

Differences between the Glycosylation Patterns of Haptoglobin Isolated from Skin Scales and Plasma of Psoriatic Patients

2012

Improved diagnosis of psoriasis, by new biomarkers, is required for evaluating the progression rate of the disease and the response to treatment. Haptoglobin (Hpt), a glycoprotein secreted by hepatocytes and other types of cells including keratinocytes, was found with glycan changes in psoriasis and other diseases. We previously reported that Hpt isolated from plasma of psoriatic patients is more fucosylated than Hpt of healthy subjects. The aim of this study was to compare the glycosylation pattern of Hpt isolated from skin scales or plasma of patients with psoriasis with that of Hpt from cornified epidermal layer or plasma of healthy subjects. High performance liquid chromatography analys…

Chemical and chemoenzymatic synthesis of glycopeptide selectin ligands containing sialyl Lewis X structures.

2010

Synthesis of tumor-associated glycopeptide antigens.

2002

Carbohydrates and peptides linked together in glycoproteins constitute important components of the molecular communication between cells in multicellular organisms. Cell morphogenesis and tumorigenesis are accompanied by changes in the glycoprotein profiles of the outer cell membranes. Glycopeptide fragments of glycoproteins that have altered structures in tumor cells are of interest as tumor-associated antigens for the distinction between normal cells and tumor cells. In contrast to glycoproteins isolated from biological sources, synthetic glycopeptides are obtained in pure form and exactly specified structures. The methods developed for the synthesis of glycopeptides with tumor-associated…