The glycosylation of platelets may prolong their life-span when being transfused after preservation under 4 degrees C, therefore this study was aimed to investigate the effect of glycosylation on morphology, ultrastructure, function and membrane glycoprotein of platelets. The experiments were divided into 3 groups: group preserved in room temperature (RT group), group preserved in 4 degrees C (4T group) and group UDP-Gal glycosylated and preserved in 4 degrees C (U+4T group). The binding rate of RCA I lectin and expression of platelet surface markers CD62P, CD42b were determined by flow cytometry. Morphology and ultrastructure of platelets were observed by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Platelets aggregation was detected by aggregometer. The results showed that the binding rate of RCAI in U+4T group significantly higher than that in RT group (p<0.01), no obvious changes was found in ultrastructure of glycosylated platelets, as compared with fresh platelets. Some morphologic changes, such as pseudopodium could be observed in 4T group. The aggregation rate of platelets in U+4T group reached to 50% of RT group. The expression levels of CD42b and CD62P, and the binding rate of annexin V in U+4T group were not significantly different from that in RT group. It is concluded that UDP-Gal can effectively cause galactosylation of platelets, and the platelets modified with UDP-Gal remain normal morphology, ultrastructure and function.
Blood Platelets ; drug effects ; physiology ; ultrastructure ; Blood Preservation ; methods ; Cryopreservation ; methods ; Galactose ; pharmacology ; Glycosylation ; Humans

This study was aimed to investigate the stability and in vitro function of glycosylated platelets concentrates after long-term refrigeration. The experiments were divided into 4 groups: group preserved at room temperature (RT group), group preserved at 4 degrees C (4T group), group glycosylated and preserved at 4 degrees C (U + 4 group) and group preserved at 4 degrees C and glycosylated (4 + U group). All groups followed for up to 14 days. The binding rate of RCA I lectin and expression of Plt surface markers CD62P, CD42b and Annexin V binding were determined by flow cytometry. pH and mean volume were determined by pH meter and hematotocytometer respectively. Platelet aggregation was detected by aggregometer. The results showed that during storage up to 14 days RCAI binding rate of modified groups was 5 - 6 fold of RT group. The pH of platelets suspension had no significant difference between these two groups (p > 0.05). Mean volumes of both groups (10.6 +/- 1.9 fL and 11.14 +/- 1.1 fL) were also no significant difference (p > 0.05). Furthermore, aggregation responsiveness of modified groups was better than that of RT groups (p < 0.05) although both decreased during the storage. The expression level of CD62P, CD42b and Annexin V binding during 5 days of storage had no significant difference between modified and fresh platelet groups (p > 0.05). While the expression level of CD62P and PS increased and the expression level of CD42b decreased during storage up to 14 days, there was significant difference between modified and fresh platelet groups (p < 0.01). It is concluded that the glycan modification is stable during storage up to 14 days. The glycosylated platelets retain in vitro function better than RT platelets during storage, but it shows activation to varying degrees in vitro after storage for 5 days.
Blood Platelets ; cytology ; metabolism ; Blood Preservation ; Cryopreservation ; methods ; Galactose ; pharmacology ; Glycosylation ; Humans ; Platelet Aggregation ; drug effects

OBJECTIVE: : To investigate the effect of chlorogenic acid (CGA) on non-enzymatic glycation and oxidation of low density lipoprotein (LDL). METHODS: : The non-enzymatic glycation incubation system of LDL-glucose was established. The contents of early glycation products (Amodori product) and intermediate products (dicarbonyl compound) were determined by ultraviolet-visible spectrophotometry, and the content of advanced glycation end products (AGEs) was determined by fluorescence spectrophotometry. The LDL oxidation incubation system was established. The contents of thiobarbituric acid reactive substances(TBARS) and conjugated diene were determined by ultraviolet-visible spectrophotometry. The tryptophan fluorescence quenching, and the content of lipofuscin, total fluorescence products, active aldehydes and malondialdehyde were determined by fluorescence spectrophotometry, and further verified by three-dimensional fluorescence spectroscopy. RESULTS: : In the LDL glycation experiment, 150 μg/mL and 300 μg/mL CGA inhibited the formation of Amadori product, dicarbonyl compounds and AGEs. In the LDL oxidation experiment, 15 μg/mL and 25 μg/mL CGA inhibited the formation of TBARS effectively; 5 μg/mL and 10 μg/mL CGA inhibited tryptophan fluorescence quenching, and the formation of active aldehydes, malondialdehyde, total fluorescence products, lipofuscin and conjugated diolefine. And the three-dimensional fluorescence spectroscopy showed the same results. CONCLUSIONS : CGA can inhibit non-enzymatic glycation and oxidation of LDL.
Chlorogenic Acid ; pharmacology ; Glycosylation ; drug effects ; Lipoproteins, LDL ; metabolism ; Oxidation-Reduction ; drug effects ; Thiobarbituric Acid Reactive Substances ; analysis

To study the effects of glycosylation on survival of cold-storage human platelets by using rabbit model. (51)Cr-labeling platelets were used to detect the platelet storage survival. The human platelets (2.0 x 10(12)/L) treated with 5 g/L uridine diphosphate galactose (UDP-Gal) were stored in 4 degrees C refrigeratory up to 10 days. The survival of human platelets in rabbits whose reticuloendothelial system was inhibited by the administration of ethyl palmitate was monitored in blood drawn at various times after the platelet transfusion. The results showed that the survival rate of platelets was significantly increased in cold-storage human platelets by UDP-Gal treatment. The survival rates of platelets at 2 hours after transfusion into rabbits in groups of fresh platelets group, UDP-Gal + cold platelets group and cold platelets group were (68.9 +/- 8.5)%, (65.4 +/- 8.0)% and (5.0 +/- 2.6)%, respectively. Compared with cold platelets group, significant differences were seen among all groups (P < 0.01). UDP-Gal + cold platelets group had no significant differences compared with fresh platelets group (P > 0.05). It is concluded that UDG-Gal can provide the protective effect on cold-storage human platelets and prolong the survival time of refrigerated human platelets in rabbit model.
Animals ; Blood Platelets ; cytology ; metabolism ; Blood Preservation ; Cell Survival ; drug effects ; Cryopreservation ; methods ; Glycosylation ; drug effects ; Humans ; Models, Animal ; Platelet Transfusion ; Rabbits ; Uridine Diphosphate Galactose ; pharmacology

AIM: To discover more active and water-soluble derivatives of tetracyclic diterpenoids containing an exo-methylene cyclopentanone or an α-methylenelactone moiety. METHODS: All of the key intermediates were synthesized from stevioside, and the target compounds were obtained through glycosylation of the 4-carboxyl group. The cytotoxicity of the target compounds against six human cancer cell lines, HepG2, Bel-7402, A549, U251, MCF-7 and MDA-MB-231, were evaluated by the MTT assay. RESULTS: Compound 1b was more effective than the positive control adriamycin against the HepG2, Bel-7402, A549, MCF-7, and MDA-MB-231 cell lines with IC50 values of 0.12, 0.91, 0.35, 0.08, and 0.07 μmol·L(-1), respectively. Moreover, compound 3c exhibited the most potent and selective cytotoxic activity against the HepG2 cell line (IC50, 0.01 μmol·L(-1)). CONCLUSION Compounds 1b and 3c could be considered as potential anticancer candidates for further study.
Antineoplastic Agents ; chemistry ; toxicity ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Diterpenes, Kaurane ; chemistry ; toxicity ; Drug Evaluation, Preclinical ; Glycosylation ; Humans ; Molecular Structure

This study is to investigate the protective effect of rosiglitazone (RSG) against learning and memory impairment of APP/PS1/tau transgenic mice. AD mice model was replicated by using 6-month APP/PS1/tau transgenic mice. The learning and memory ability of mice was evaluated by Morris water maze and Western blotting assays was applied to measure the phosphorylation and O-glycosylation of Tau and neurofilaments (NFs) protein. The results demonstrated that RSG could reverse the learning and memory deficits of 3 x Tg mice significantly. It was also found that RSG could suppress the hyperphosphorylation of Tau and NFs protein levels and increase the glycosylation expression of Tau and NFs proteins in 3 x Tg mice brain. Together, RSG ameliorates cognitive impairments of 3 x Tg mice via the alleviation of the hyperphosphorylated Tau and NFs proteins burden in the brain.
Alzheimer Disease ; Amyloid beta-Peptides ; Animals ; Brain ; drug effects ; Disease Models, Animal ; Glycosylation ; Learning ; drug effects ; Memory ; drug effects ; Memory Disorders ; drug therapy ; Mice ; Mice, Transgenic ; Neurofilament Proteins ; metabolism ; Phosphorylation ; Thiazolidinediones ; pharmacology ; tau Proteins ; metabolism

The present study was designed to evaluate the therapeutic potential of bioactive compounds from chloroform extract of the leaves of Hylocereus undatus in the formation of advanced glycation end products (AGEs) in vitro. Bioactivity-guided fractionation of chloroform extract from Hylocereus undatus afforded two novel 12-ursen-type triterpenes, 3β, 16α, 23-trihydroxy-urs-12- en-28-oic acid (1) and 3β, 6β, 19α, 22α-tetrahydroxy-urs-12-en-28-oic acid (2), as well as four known triterpenes 2α, 3β, 23-tetrahydroxy-urs-11-en-28-oic acid (3), 3β-acetoxy-28-hydroxyolean-12-ene (4), 3β, 16α-dihidroxyolean-12-ene (5) and 3β-acetoxy-olean-12-ene (6). Our results revealed that triterpenes 1-3 were able to inhibit the formation of AGEs in all tested assays. The data indicated that the triterpenes had inhibitory activity at the múltiple stages of glycation and that there might be a high potential for decreasing protein oxidation and protein glycation that can enhance glycative stress in diabetic complications.
Cactaceae ; chemistry ; Glycation End Products, Advanced ; chemistry ; Glycosylation ; drug effects ; Molecular Structure ; Plant Extracts ; chemistry ; isolation & purification ; pharmacology ; Plant Leaves ; chemistry ; Triterpenes ; chemistry ; isolation & purification ; pharmacology

The formation of advanced glycation end products (AGEs) has been considered to be a potential causative factor of injury to lens epithelial cells (LECs). Damage of LECs is believed to contribute to cataract formation. The purpose of this study was to investigate the cytotoxic effect of AGEs on LECs both in vitro and in vivo. We examined the accumulation of argpyrimidine, a methylglyoxal-derived AGE, and the expression of apoptosis-related molecules including nuclear factor-kappaB (NF-kappaB), Bax, and Bcl-2 in the human LEC line HLE-B3 and in cataractous lenses of Zucker diabetic fatty (ZDF) rats, an animal model of type 2 diabetes. In cataractous lenses from twenty-one-week-old ZDF rats, LEC apoptosis was markedly increased, and the accumulation of argpyrimidine as well as subsequent activation of NF-kappaB in LECs were significantly enhanced. The ratio of Bax to Bcl-2 protein levels was also increased. In addition, the accumulation of argpyrimidine triggered apoptosis in methylglyoxal-treated HLE-B3 cells. However, the presence of pyridoxamine (an AGEs inhibitor) and pyrrolidine dithiocarbamate (a NF-kappaB inhibitor) prevented apoptosis in HLE-B3 cells through the inhibition of argpyrimidine formation and the blockage of NF-kappaB nuclear translocalization, respectively. These results suggest that the cellular accumulation of argpyrimidine in LECs is NF-kappaB-dependent and pro-apoptotic.
Animals ; Apoptosis/*drug effects ; Cell Line ; Epithelial Cells/*cytology/*drug effects ; Glycosylation End Products, Advanced/*pharmacology ; Lens, Crystalline/*cytology ; Male ; Ornithine/*analogs & derivatives/pharmacology ; Pyrimidines/*pharmacology ; Pyruvaldehyde/*chemistry ; Rats

Endoplasmic reticulum (ER) stress regulates a wide range of cellular responses including apoptosis, proliferation, inflammation, and differentiation in mammalian cells. In this study, we observed the role of 2-deoxy-D-glucose (2DG) on inflammation of chondrocytes. 2DG is well known as an inducer of ER stress, via inhibition of glycolysis and glycosylation. Treatment of 2DG in chondrocytes considerably induced ER stress in a dose- and time-dependent manner, which was demonstrated by a reduction of glucose regulated protein of 94 kDa (grp94), an ER stress-inducible protein, as determined by a Western blot analysis. In addition, induction of ER stress by 2DG led to the expression of COX-2 protein with an apparent molecular mass of 66-70kDa as compared with the normally expressed 72-74 kDa protein. The suppression of ER stress with salubrinal (Salub), a selective inhibitor of eif2-alpha dephosphorylation, successfully prevented grp94 induction and efficiently recovered 2DG-modified COX-2 molecular mass and COX-2 activity might be associated with COX-2 N-glycosylation. Also, treatment of 2DG increased phosphorylation of Src in chondrocytes. The inhibition of the Src signaling pathway with PP2 (Src tyrosine kinase inhibitor) suppressed grp94 expression and restored COX-2 expression, N-glycosylation, and PGE2 production, as determined by a Western blot analysis and PGE2 assay. Taken together, our results indicate that the ER stress induced by 2DG results in a decrease of the transcription level, the molecular mass, and the activity of COX-2 in rabbit articular chondrocytes via a Src kinase-dependent pathway.
Animals ; Cartilage, Articular/pathology ; Cells, Cultured ; Chondrocytes/drug effects/immunology/*metabolism/pathology ; Cyclooxygenase 2/genetics/*metabolism ; Deoxyglucose/*pharmacology ; Down-Regulation ; Endoplasmic Reticulum/drug effects/*metabolism/pathology ; Glycosylation/drug effects ; Inflammation ; Rabbits ; Signal Transduction/drug effects ; Stress, Physiological/drug effects/immunology ; src-Family Kinases/*metabolism

OBJECTIVEOver the last few decades, diabetic cardiomyopathy has been identified as a significant contributor in cardiac morbidity. However, the mechanisms of diabetic cardiomyopathy have not been clarified.

METHODSIn the present study, a diabetic rat model was induced by the intraperitoneal injection of streptozotocin. The myocardial CD147 expression and extent of glycosylation, as well as thematrixmetalloproteinases(MMPs) expression and activity, were observed in the diabetic and synchronous rats.

RESULTSThe results showed that CD147 located on sarcolemma of cardiomyocytes. The myocardial CD147 expression and glycosylation were significantly increased in the diabetic rats as compared with the control. Expression of MMP-2 protein, MMP-2 and MMP-9 activity were also increased in left ventricular myocardium in the diabetic rats. Tamoxifen only inhibited the enhanced expression of myocardial CD147 in the diabetic rats, but not in synchronous control rats. Tamoxifen inhibited glycosylation of myocardial CD147 in both diabetic and control rats. The inhibition of tamoxifen on CD147 glycosylation was stronger than on the expression in the myocardium. The extent of myocardial CD147glycosylation was positively related toMMP-2 and MMP-9 activity. Tamoxifen induced an inhibition of myocardial MMP-2 and MMP-9 activity in the control and diabetic rats.

CONCLUSIONThese results indicate that myocardial CD147 expression, especially the extent of glycosylation, regulates MMP-2 and MMP-9 activity, then accelerates cardiac pathological remodeling inducing diabetic cardiomyopathy. Tamoxifen inhibits myocardial CD147 glycosylation and further depress the activity of MMPs. Therefore, tamoxifen may protect the diabetic rats against diabetic myocardium.

Animals ; Basigin ; metabolism ; Diabetes Mellitus, Experimental ; complications ; Diabetic Cardiomyopathies ; drug therapy ; Glycosylation ; Heart ; drug effects ; Matrix Metalloproteinase 2 ; metabolism ; Matrix Metalloproteinase 9 ; metabolism ; Myocardium ; metabolism ; Myocytes, Cardiac ; cytology ; Rats ; Sarcolemma ; metabolism ; Tamoxifen ; pharmacology