Perinatal Protein Restriction Impacts Nuclear O-GalNAc Glycosylation in Cells of Liver and Brain Structures of the Rat.

BACKGROUND: Post-translational modifications are key factors in the modulation of nuclear protein functions controlling cell physiology and an individual's health. OBJECTIVES: This study examined the influence of protein restriction during the perinatal period on the nuclear O-N-acetylgalactosamine (O-GalNAc) glycosylation of cells from the liver and parts of the brain in the rat. METHODS: Pregnant Wistar rats were divided into 2 groups on day 14 of pregnancy and fed ad libitum 1 of 2 isocaloric diets containing 24% (well-fed) or 8% (protein-restricted diet) casein until the end of the experiment. Male pups were studied after weaning at 30 d of life. Animals and their organ/tissues (liver, cerebral cortex, cerebellum and hippocampus) were weighed. Cell nuclei were purified, and the presence in nucleus and cytoplasm of all factors required for the initiation of O-GalNAc glycan biosynthesis, i.e., the sugar donor (UDP-GalNAc), enzyme activity (ppGalNAc-transferase) and the glycosylation product (O-GalNAc glycans), were evaluated by western blotting, fluorescent microscopy, enzyme activity, enzyme-lectin sorbent assay and mass spectrometry. RESULTS: The perinatal protein deficit reduced progeny weight, as well as the cerebral cortex and cerebellum weight. UDP-GalNAc levels in the cytoplasm and nuclei of the liver, the cerebral cortex, cerebellum, or hippocampus were not affected by the perinatal dietary protein deficits. However, this deficiency affected the ppGalNAc-transferase activity localized in the cerebral cortex and hippocampus cytoplasm as well as in the liver nucleus, thus reducing the "writing" ppGalNAc-transferase activity of O-GalNAc glycans. In addition, liver nucleoplasm from protein-restricted offspring revealed a significant reduction in the expression of O-GalNAc glycans on important nuclear proteins. CONCLUSIONS: Our results report an association between the consumption of a protein-restricted diet by the dam and her progeny with the modulation in the offspring' liver nuclei O-GalNAc glycosylation, which may ultimately regulate nuclear protein functions.

[The Activity Characteristics of ABO Blood Group Glycosyltransferases and the Effect of Plasma Preservation on its activity].

OBJECTIVE: Activities of ABO blood group glycosyltransferases in the plasma of blood donors with different blood groups were detected to discover their normal ranges. In addition, the influence of different plasma storage temperatures and time on the enzyme activity was studied, so as to establish a stable ABO blood group glycosyltransferase activity detection technology system for the auxiliary identification of ABO blood groups. METHODS: Detect the activities of glycosyltransferase A (GTA) in plasma of type A, AB and O blood donors, and glycosyltransferase B (GTB) in plasma of type B, AB and O blood donors, respectively, to determine the activity range of GTA and GTB in the plasma of normal blood group under this detection technique. RESULTS: The activities of GTA and GTB in plasma of the same ABO blood groups were relatively consistent, while significant difference was found among different ABO blood groups. The activity of GTA was around 27.9±0.3 in plasma of A blood group and 28.3±0.5 in plasma of AB blood group. The activity of GTB in plasma of B blood group was about 24.4±0.5, and that in plasma of AB blood group was about 25.6±0.5. The activities of GTA and GTB in plasma of O blood group were negative. The storage temperature and time of plasma would affect the activities of GTA and GTB. There were no significant changes of the activities of GTA and GTB when the plasma was stored at 4 ℃ for 7 days and -40℃ for 21 days. However, after 28 days of storage at -40 ℃, the activities of GTA and GTB were both decreased significantly. CONCLUSION: The preservation condition suitable for the detection of ABO glycosyltransferase activity in plasma samples contain short-term storage at 4 ℃ for one week, and cryopreserved at -40 ℃ for no more than three weeks.

ABO blood group, glycosyltransferase activity and risk of venous thromboembolism.

INTRODUCTION: ABO blood group influence the risk of venous thromboembolism (VTE) by modifying A and B glycosyltransferases (AGT and BGT) activities that further modulates Factor VIII (FVIII) and von Willebrand Factor (VWF) plasma levels. The aim of this work was to evaluate the association of plasma GTs activities with VWF/FVIII plasma levels and VTE risk in a case-control study. MATERIALS AND METHODS: 420 cases were matched with 420 controls for age and ABO blood group. GT activities in plasma were measured using the quantitative transfer of tritiated N-acetylgalactosamine or galactose to the 2'-fucosyl-lactose and expressed in disintegration per minute/30 µL of plasma and 2 h of reaction (dpm/30 µL/2H). FVIII and VWF plasma levels were respectively measured using human FVIII-deficient plasma in a 1-stage factor assay and STA LIATEST VWF (Diagnostica Stago). RESULTS: A and B GT activities were significantly lower in cases than in controls (8119 ± 4027 vs 9682 ± 4177 dpm/30 µL/2H, p = 2.03 × 10-5, and 4931 ± 2305 vs 5524 ± 2096 dpm/30 µL/2H, p=0.043 respectively). This association was observed whatever the ABO blood groups. The ABO A1 blood group was found to explain~80% of AGT activity. After adjusting for ABO blood groups, AGT activity was not correlated to VWF/FVIII plasma levels. Conversely, there was a moderate correlation (ρ ~ 0.30) between BGT activity and VWF/ FVIII plasma levels in B blood group carriers. CONCLUSION: Work showed, for the first time, that GT activities were decreased in VTE patients in comparison to controls with the same ABO blood group. The biological mechanisms responsible for this association remained to be determined.

Purification, characterization and function analysis of an extracellular ß-glucosidase from elongating stipe cell walls in Coprinopsis cinerea.

A ß-glycoside hydrolase was isolated from cell walls material in Coprinopsis cinerea elongating stipes. By analysis of SDS-PAGE, MALDI-TOF/TOF MS and substrate specificity, this enzyme was characterized as an extracellular ß-glucosidase which is a trimer consisting of three homosubunits. ß-Glucosidase did not degrade ß-glucans with modified ends, whereas it hydrolyzed various ß-glucans with free ends and related oligosaccharides with ß-1,3-, ß-1,4- or ß-1,6-linkages. Although this ß-glucosidase possesses glycosyltransferase activity on laminarioligosaccharides, it did not transfer glucose residues from laminaritriose to ß-glucan in stipe cell walls to produce larger ß-glucan molecules; instead, it caused a decrease in the molecular size of stipe wall ß-glucan by removing glucose. Relatively, the molecular size of wall ß-glucans in the elongating apical stipe was less than that found in the non-elongating basal stipes, and this ß-glucosidase was more highly expressed in the elongating apical stipe than in non-elongating basal regions. Therefore, we propose that ß-glucosidase functions by trimming or cutting the ß-glucan side chains on the ß-1,3-glucan backbone to prevent them from forming longer branches, keeping the wall plastic to promote diffuse wall growth.

Advances in multifunctional glycosylated nanomaterials: preparation and applications in glycoscience.

Applications of glycosylated nanomaterials have gained considerable attention in recent years due to their unique structural properties and compatibility in biological systems. In this review, glyco-nanoparticles (glyco-NPs) are defined as compounds that contain a nano-sized metallic core, are composed of noble metals, magnetic elements, or binary inorganic nanoparticles, and that exhibit carbohydrate ligands on the surface in three dimensional polyvalent displays similar to the glycocalyx structures on cell membranes. Nanomaterials decorated with suitable biological recognition ligands have yielded novel hybrid nanobiomaterials with synergistic functions, especially in biomedical applications. This review focuses on strategies for building various types of glyco-NPs and highlights their potential in targeted drug delivery and molecular imaging as well as their uses in bioassays and biosensors. The most recent examples of glyco-NPs as vaccine candidates and probes for assaying enzymes with bond-forming activities are also discussed.