N-acetyl-D-glucosamine Dotaz Zobrazit nápovědu

Přesná shoda Sémantické

68 záznamů v Medvik

Článek

Antitumor activity of N-acetyl-D-glucosamine-substituted glycoconjugates and combined therapy with keyhole limpet hemocyanin in B16F10 mouse melanoma model

... N-Acetyl-D-glucosamine-substituted glycoconjugates (GCJs) with the polyamidoamine (GN8P) or calix[4]arene ...

Folia microbiologica. 2010 ; 55 (5) : 528-532.

Medvik
Zdroj

N-Acetyl-D-glucosamine-substituted glycoconjugates (GCJs) with the polyamidoamine (GN8P) or calix[4]arene (GN4C) scaffold represent ligands for NKR-P1 molecule and induce NK cell-mediated cytotoxicity in vitro. The in vivo effect of these GCJs on mouse melanoma model was determined when administered either alone or in combination with non-specific immunostimulator keyhole limpet hemocyanin (KLH). All types of treatment significantly reduced the tumor growth on day 23, while GN4C as well as KLH were effective continuously (from day 14). The GN4C also induced the longest mean survival time (46.3 ± 11.1 d), followed by KLH+GN4C (36.4 ± 12.1), KLH (35.6 ± 6.5), KLH+GN8P (35.6 ± 6.7), and GN8P (32.4 ± 7.0), compared to controls (29.8 ± 3.6). The B16F10 specific cytotoxicity of peripheral blood cells was significantly elevated by both KLH and GN8P, whereas not by GN4C. KLH increased the effect of the GN4C, but did not influence that of GN8P. GN4C was proved to exert anticancer activity in mouse melanoma model. The combination of KLH with GCJs did not generate synergism.

Článek

N-acetyl-D-glucosamine-coated polyamidoamine dendrimer promotes tumor-specific B cell responses via natural killer cell activation

... N-acetyl-D-glucosamine-coated polyamidoamine dendrimer (GN8P), exerting high binding affinity to rodent ...

International immunopharmacology. 2011 ; 11 (8) : 955-961. [pub] 20110222

Int Immunopharmacol
ISSN 1878-1705
Medvik
Zdroj

N-acetyl-D-glucosamine-coated polyamidoamine dendrimer (GN8P), exerting high binding affinity to rodent recombinant NKR-P1A and NKR-P1C activating proteins, was shown previously to delay the development of rat colorectal carcinoma as well as mouse B16F10 melanoma, and to potentiate antigen-specific antibody formation in healthy C57BL/6 mice via NK cell stimulation. In this study, we investigated whether GN8P also modulates tumor-specific B cell responses. Serum anti-B16F10 melanoma IgG levels, IgG2a mRNA expression, antibody dependent cell-mediated cytotoxicity (ADCC), and counts of plasma as well as antigen presenting B cells were evaluated in tumor-bearing C57BL/6 mice treated with GN8P and in respective controls. To reveal the mechanism of GN8P effects, the synthesis of interferon-gamma (IFN-γ) and interleukin-4 (IL-4), cytokines involved in regulation of immunoglobulin class switch, was determined. The GN8P treatment significantly elevated IgG, and particularly IgG2a, response against B16F10 melanoma, which led to augmented ADCC reaction. The significant increase in production of IFN-γ, which is known to support IgG2a secretion, was observed solely in NK1.1 expressing cell populations, predominantly in NK cells. Moreover, GN8P raised the number of plasma cells, and promoted antigen presenting capacity of I-A/I-E-positive B lymphocytes by up-regulation of their CD80 and CD86 co-stimulatory molecule expression. These results indicate that GN8P-induced enhancement of tumor-specific antibody formation is triggered by NK cell activation, and contributes to complexity of anticancer immune response involving lectin-saccharide interaction.

Článek

N-acetyl-D-glucosamine substituted calix[4]arenes as stimulators of NK cell-mediated antitumor immune response

Carbohydrate research. 2007 ; 342 (12-13) : 1781-1792.

ISSN 0008-6215
Medvik
Zdroj

A series of calixarenes substituted with 2-acetamido-2-deoxy-beta-D-glucopyranose linked by a thiourea spacer was prepared and tested for binding activity to heterogeneously expressed activation receptors of the rat natural killer cells NKR-P1, and the receptor CD69 (human NK cells, macrophages). In the case of NKR-P1, the binding affinity of beta-D-GlcNAc-substituted calixarenes carrying two or four sugar units was in a good agreement with the inhibitory potencies of the linear chitooligomers (chitobiose to chitotetraose) reported previously. The influence of GlcNAc substitution of the calixarene skeleton on binding affinity for CD69 receptor was more profound and the 5,11,17,23-tetrakis[N-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-thioureido]-25,26,27,28-tetrapropoxycalix[4]arene (cone) (1) proved to be the best CD69 ligand identified to date. Lower GlcNAc substitution led to dramatic decrease of the binding activity (by about 1.5 order of magnitude per one GlcNAc unit). The immunostimulating activity results with the newly synthesized GlcNAc tetramers on calixarene scaffolds exhibited stimulation of natural cytotoxicity of human PBMC in concentrations 10(-4) and 10(-8)M. These calix-sugar compounds were superior to the previously tested PAMAM-GlcNAc(8)5.

Článek

N-Acetyl-D-glucosamine-coated polyamidoamine dendrimer modulates antibody formation via natural killer cell activation

... N-Acetyl-D-glucosamine-coated polyamidoamine dendrimer (GlcNAc8) was shown previously to exhibit binding ...

International immunopharmacology. 2009 ; 9 (6) : 792-799.

Int Immunopharmacol
Medvik
Zdroj

N-Acetyl-D-glucosamine-coated polyamidoamine dendrimer (GlcNAc8) was shown previously to exhibit binding affinity to the rat recombinant NKR-P1 molecule (known in mice also as NK1.1) and to induce NK cell-mediated cytotoxicity. In this study, we investigated whether GlcNAc8 modulates antibody formation as activated NK cells were reported to participate in its regulation. C57BL/6 mice treated with GlcNAc8 and intact controls were immunized either with sheep red blood cells (SRBCs), 2,4-dinitrophenylated-lipopolysaccharide (DNP-LPS) or keyhole limpet hemocyanin (KLH) for evaluation of splenic antibody forming cell counts and serum immunoglobulin (Ig) levels. In vitro Ig formation was determined using supernatants of spleen mononuclear cells (SMCs) and CD49b or NK1.1-depleted SMC subpopulations. Serum antigen-specific IgG2a levels were also measured in DBA/2 and BALB/c mice (NK1.1-negative mouse strains on the basis of flow cytometric analysis) which possess different Nkr-p1c gene form than C57BL/6 ones. A significant increase in anti-SRBC IgG forming cells, serum levels of anti-KLH as well as anti-DNP IgG and IgG2a was observed after GlcNAc8 administration in C57BL/6 mice. IgM levels in supernatants of SMCs stimulated in vitro simultaneously with DNP-LPS and GlcNAc8 were significantly mounted compared with supernatants of SMCs primed with the antigen alone, but this enhancement was blocked after depletion of CD49b-positive or NK1.1-positive cells. In DBA/2 and BALB/c mice, GlcNAc8 influenced neither serum levels of anti-KLH nor anti-DNP IgG2a. These results indicate that GlcNAc8-induced upregulation of antibody formation is triggered by NK cell stimulation and depends on expressed NKR-P1 isoforms, particularly NKR-P1C.

Článek

[RETRACTED] Synthetic N-acetyl-D-glucosamine based fully branched tetrasaccharide, a mimetic of the endogenous ligand for CD69, activates CD69+ killer lymphocytes upon dimerization via a hydrophilic flexible linker

Journal of medicinal chemistry. 2010 ; 53 (10) : 4050-4065.

J Med Chem
ISSN 1520-4804
Medvik
Zdroj

On the basis of the highly branched ovomucoid-type undecasaccharide that had been shown previously to be an endogenous ligand for CD69 leukocyte receptor, a systematic investigation of smaller oligosaccharide mimetics was performed based on linear and branched N-acetyl-d-hexosamine homooligomers prepared synthetically using hitherto unexplored reaction schemes. The systematic structure-activity studies revealed the tetrasaccharide GlcNAcbeta1-3(GlcNAcbeta1-4)(GlcNAcbeta1-6)GlcNAc (compound 52) and its alpha-benzyl derivative 49 as the best ligand for CD69 with IC(50) as high as 10(-9) M. This compound thus approaches the affinity of the classical high-affinity neoglycoprotein ligand GlcNAc(23)BSA. Compound 68, GlcNAc tetrasaccharide 52 dimerized through a hydrophilic flexible linker, turned out to be effective in activating CD69(+) lymphocytes. It also proved efficient in enhancing natural killing in vitro, decreasing the growth of tumors in vivo, and activating the CD69(+) tumor infiltrating lymphocytes examined ex vivo. This compound is thus a candidate for carbohydrate-based immunomodulators with promising antitumor potential.

Článek online

Monosaccharide profiling of glycoproteins by capillary electrophoresis with contactless conductivity detection

... conductivity detection for the separation of eight monosaccharides commonly found in glycoproteins, namely D-glucose ...

Electrophoresis. 2022 ; 43 (20) : 1963-1970. [pub] 20220827

ISSN 1522-2683
Medvik
Zdroj

Saccharides form one of the major constituents of biological macromolecules in living organisms. Many biological processes including protein folding, stability, immune response and receptor activation are regulated by glycosylation. In this work, we optimized a capillary electrophoresis method with capacitively coupled contactless conductivity detection for the separation of eight monosaccharides commonly found in glycoproteins, namely D-glucose, D-galactose, D-mannose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, D-fucose, N-acetylneuraminic acid, and D-xylose. A highly alkaline solution of 50 mM sodium hydroxide, 22.5 mM disodium phosphate, and 0.2 mM CTAB (pH 12.4) was used as a background electrolyte in a 10 μm id capillary. To achieve baseline separation of all analytes, a counter-directional pressure of -270 kPa was applied during the separation. The limits of detection of our method were below 7 μg/ml (i.e., 1.5 pg or 1 mg/g protein) and the limits of quantification were below 22 μg/ml (i.e., 5 pg or 3 mg/g protein). As a proof of concept of our methodology, we performed an analysis of monosaccharides released from fetuin glycoprotein by acid hydrolysis. The results show that, when combined with an appropriate pre-concentration technique, the developed method can be used as a monosaccharide profiling tool in glycoproteomics and complement the routinely used LC-MS/MS analysis.

Článek online

Mouse acidic mammalian chitinase exhibits transglycosylation activity at somatic tissue pH

... Mouse AMCase produces primarily dimers of N-acetyl-d-glucosamine [(GlcNAc)2 ] under both pH conditions ...

FEBS letters. 2017 ; 591 (20) : 3310-3318. [pub] 20170830

FEBS Lett
ISSN 1873-3468
Medvik
Zdroj

Mouse acidic mammalian chitinase (AMCase) degrades chitin with highest efficiency at pH 2.0 and is active up to pH 8.0. Here, we report that mouse AMCase also exhibits transglycosylation activity under neutral conditions. We incubated natural and artificial chitin substrates with mouse AMCase at pH 2.0 or 7.0 and analyzed the resulting oligomers using an improved method of fluorescence-assisted carbohydrate electrophoresis. Mouse AMCase produces primarily dimers of N-acetyl-d-glucosamine [(GlcNAc)2 ] under both pH conditions while generating transglycosylated (GlcNAc)3 primarily at pH 7.0 and at lower levels at pH 2.0. These results indicate that mouse AMCase catalyzes hydrolysis as well as transglycosylation and suggest that this enzyme can play a novel role under physiological conditions in peripheral tissues, such as the lungs.

MeSH
acetylglukosamin metabolismus MeSH
chitin metabolismus MeSH
chitinasy genetika metabolismus MeSH
dimerizace MeSH
elektroforéza metody MeSH
Escherichia coli genetika metabolismus MeSH
exprese genu MeSH
fluorescence MeSH
glykosylace MeSH
hydrolýza MeSH
kinetika MeSH
klonování DNA MeSH
koncentrace vodíkových iontů MeSH
myši MeSH
plíce enzymologie MeSH
rekombinantní proteiny genetika metabolismus MeSH
zvířata MeSH
Check Tag
myši MeSH
zvířata MeSH
Publikační typ
dopisy MeSH
práce podpořená grantem MeSH

Článek

Preparation of hyaluronan polyaldehyde-a precursor of biopolymer conjugates

... Selective oxidation of primary hydroxyl groups of N-acetyl-D-glucosamine of hyaluronan was performed ...

Carbohydrate research. 2013 ; 371 () : 8-15.

Carbohydr Res
ISSN 1873-426X
Medvik
Zdroj

Native hyaluronan (HA) has been oxidized to polyaldehyde polymers with a degree of substitution (DS) of up to 50%. Two different procedures enabling the control of the degree of substitution were followed in this study. Selective oxidation of primary hydroxyl groups of N-acetyl-D-glucosamine of hyaluronan was performed either in an aqueous solution containing AcNH-TEMPO/NaBr/NaOCl or in an aprotic solvent containing Dess-Martin periodinane (DMP). It was found that a change of reaction parameters (reaction time and temperature, type of catalyst, oxidant-to-HA ratio, presence of nitrogen, buffer type, and concentration) had an influence on the degree of substitution and molecular weight. The derivatives were characterized by MS, NMR spectroscopy, and SEC-MALLS. Degradation of hyaluronic acid by the oxidant was observed and confirmed by SEC. The effect of oxidized derivatives of hyaluronan on cells was studied by means of NIH 3T3 fibroblast viability, which indicates that prepared hyaluronan polyaldehydes are biocompatible and suitable for medical applications and tissue engineering. The function of polyaldehyde as precursor for other modification was illustrated in the reaction with lysine.