Oxidative Phosphorylation ; Acetylglucosamine ; Uridine Diphosphate N-Acetylglucosamine/metabolism*

PURPOSE: Poly-N-acetyl glucosamine(PGlcNAc) nanofiber-based materials, produced by a marine microalga, have been characterized as effective hemostatic and angiogenic agents. The similarity between PGlcNAc patch and the natural extracellular matrix allows it to support new healthy tissue growth in an injured area and to encourage fluid absorption. In this study, we hypothesized that a poly-N-acetyl glucosamine fiber patch(PGlcNAc patch) may enhance wound healing in the db/db mouse. METHODS: PGlcNAc patches were applied on one square centimeter, full-thickness, skin wounds in the db/db mouse model. Wounds(n=15 per group) were dressed with a PGlcNAc nanofiber patch for 1 hour(1h), 24 hours(24h) or left untreated(NT). After the application time, patches were removed and wounds were allowed to heal spontaneously. The rate of wound closure was evaluated by digital analysis of unclosed wound area in course of time. At day 10, wounds(n=7 per group) were harvested and quantified with immunohistochemical markers of proliferation(Ki-67) and vascularization (platelet endothelial cell adhesion molecule, PECAM-1). RESULTS: Wounds dressed with PGlcNAc patches for 1 hour closed faster than control wounds, reaching 90% closure in 16.6 days, nine days faster than untreated wounds. Granulation tissue showed higher levels of proliferation and vascularization following 1h treatment than the 24h and NT groups. In addition to its hemostatic properties, the PGlcNAc material also appears to accelerate wound closure in healing-impaired genetically diabetic mice. CONCLUSION: This material, with its combination of hemostatic and wound healing properties, has the potential to be effective agent for the treatment of complicated wounds.
Absorption ; Acetylglucosamine ; Animals ; Endothelial Cells ; Extracellular Matrix ; Glucosamine ; Granulation Tissue ; Mice ; Nanofibers ; Skin ; Wound Healing

Hyaluronic acid (HA) has long been studied in diverse applications. It is a naturally occurring linear polysaccharide in a family of unbranched glycosaminoglycans, which consists of repeating di-saccharide units of N-acetyl-D-glucosamine and D-glucuronic acid. It is almost ubiquitous in humans and other vertebrates, where it participates in many key processes, including cell signaling, tissue regeneration, wound healing, morphogenesis, matrix organization, and pathobiology. HA is biocompatible, biodegradable, muco-adhesive, hygroscopic, and viscoelastic. These unique physico-chemical properties have been exploited for several medicinal purposes, including recent uses in the adjuvant treatment for chronic inflammatory disease and to reduce pain and accelerate healing after third molar intervention. This review focuses on the post-operative effect of HA after third molar intervention along with its various physio-chemical, biochemical, and pharmaco-therapeutic uses.
Acetylglucosamine ; Biocompatible Materials ; Glycosaminoglycans ; Humans ; Hyaluronic Acid ; Molar, Third ; Morphogenesis ; Regeneration ; Vertebrates ; Wound Healing

β-N-acetylglucosaminidases (NAGases) can convert natural substrates such as chitin or chitosan to N-acetyl-β-D glucosamine (GlcNAc) monomer that is wildly used in medicine and agriculture. In this study, the BcNagZ gene from Bacillus coagulans DMS1 was cloned and expressed in Escherichia coli. The recombinant protein was secreted into the fermentation supernatant and the expression amount reached 0.76 mg/mL. The molecular mass of purified enzyme was 61.3 kDa, and the specific activity was 5.918 U/mg. The optimal temperature and pH of the BcNagZ were 75 °C and 5.5, respectively, and remained more than 85% residual activity after 30 min at 65 °C. The Mie constant Km was 0.23 mmol/L and the Vmax was 0.043 1 mmol/(L·min). The recombinant BcNagZ could hydrolyze colloidal chitin to obtain trace amounts of GlcNAc, and hydrolyze disaccharides to monosaccharide. Combining with the reported exochitinase AMcase, BcNagZ could produce GlcNAc from hydrolysis of colloidal chitin with a yield over 86.93%.
Acetylglucosamine ; Acetylglucosaminidase ; Bacillus coagulans ; Chitin ; Chitinases ; Hydrogen-Ion Concentration ; Recombinant Proteins/genetics*

Glucosamine (GlcN), also called amino sugar, is a compound derived from the substitution of a hydroxyl group of glucose molecule with an amino group. GlcN finds a wide-range of applications in health food and pharmaceutical industries. In our previous research, a recombinant Escherichia coli-glms-gnal was constructed for the efficient production of GlcN and N-acetylglucosamine (GlcNAc), the latter can be readily deacetylated to GlcN under mild acidic conditions. However, the results indicated that the titer of GlcN and GlcNAc decreased significantly due to the transportation of GlcN and GlcNAc from the culture broth to the inside of cells. To alleviate or block the transportation process, nagE gene (encoding for the GlcNAc-specific transporter) and manX gene (encoding for the mannose transporter) were knocked out with the Red homologous recombination method, and two engineered strains, E. coli-glms-gna1-delta nagE (with nagE gene deletion) and E. coli-glms-gna1-delta nagE-delta manX (with nagE and manX genes deletion), were successfully constructed. The two strains were cultured in a 7-L fermentor for the production of GlcN and GlcNAc. The maximal GlcN concentration of control strain E. coli-glms-gnal reached 4.06 g/L, and the maximal GlcNAc concentration reached 41.46 g/L. The maximal GlcN and GlcNAc concentration of E. coli-glms-gna1-delta nagE reached 4.38 g/L and 71.80 g/L, respectively, which were 1.08-fold and 1.70-fold of those of E. coli-glms-gnal, respectively. The maximal GlcN and GlcNAc concentration of E. coli-glms-gnal-delta nagE-delta manX reached 4.82 g/L and 118.78 g/L, respectively, which were 1.20-fold and 2.86-fold of those of E. coli-glms-gnal, respectively. These results suggested that the deletion of nagE and manX could significantly increase the extracellular accumulation of GlcN and GlcNAc. The results obtained here maybe useful for the microbial GlcN production in an industrial scale.
Acetylglucosamine ; biosynthesis ; genetics ; Escherichia coli ; genetics ; metabolism ; Escherichia coli Proteins ; genetics ; Gene Knockout Techniques ; Glucosamine ; biosynthesis ; genetics ; Repressor Proteins ; genetics

Dynamic changes of the post-translational O-GlcNAc modification (O-GlcNAcylation) are controlled by O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) and the glycoside hydrolase O-GlcNAcase (OGA) in cells. O-GlcNAcylation often occurs on serine (Ser) and threonine (Thr) residues of the specific substrate proteins via the addition of O-GlcNAc group by OGT. It has been known that O-GlcNAcylation is not only involved in many fundamental cellular processes, but also plays an important role in cancer development through various mechanisms. Recently, accumulating data reveal that O-GlcNAcylation at histones or non-histone proteins can lead to the start of the subsequent biological processes, suggesting that O-GlcNAcylation as 'protein code' or 'histone code' may provide recognition platforms or executive instructions for subsequent recruitment of proteins to carry out the specific functions. In this review, we summarize the interaction of O-GlcNAcylation and epigenetic changes, introduce recent research findings that link crosstalk between O-GlcNAcylation and epigenetic changes, and speculate on the potential coordination role of O-GlcNAcylation with epigenetic changes in intracellular biological processes.
Acetylglucosamine ; metabolism ; Animals ; Epigenesis, Genetic ; Glycoside Hydrolases ; metabolism ; Humans ; N-Acetylglucosaminyltransferases ; metabolism ; Neoplasms ; genetics ; metabolism ; Protein Processing, Post-Translational

Nicotinamide at millimolar concentrations affects cell survival in various conditions, and is being utilized therapeutically in many human diseases. However, the effect of an acute treatment of nicotinamide at such high dose on gene expression and cellular metabolism has rarely been determined previously. In this study, we found that levels of O-N-acetylglucosamin(O- GlcNAc)ylated proteins including Sp1 acutely decreased upon treatment of 10 mM nicotinamide. Concomitantly, Sp1 protein level decreased rapidly through accelerated proteasome-mediated proteolysis. Cotreatment of glucosamine or 2-deoxyglucose, which inhibits protein deGlcNAcylation, effectively blocked the decrease induced by nicotinamide. Interestingly, the decline in the levels of Sp1 and protein O- GlcNAcylation was only transient lasting for two days post treatment, and this pattern matched closely the rapid fluctuation of the cellular [NAD(+)]. Our results suggest a possible link between cellular nicotinamide metabolism and protein O-GlcNAcylation, and an existence of cellular [NAD(+)] homeostasis.
Acetylglucosamine/*metabolism ; Blotting, Western ; Dose-Response Relationship, Drug ; Down-Regulation/*drug effects ; Humans ; Hydrolysis ; Niacinamide/*pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; Sp1 Transcription Factor/metabolism

This study is undertaken to modify the chitosan nanoparticles (CS-NPs) with wheat germ agglutinin (WGA), and investigate the conjugation between WGA-CS-NPs and N-acetylglucosamine (NAG). CS-NPs were prepared by ionotropic gelation process and then conjugated with WGA under the activation of glutaricdialdehyde. The mean diameter of the CS-NPs was approximately 113.5 nm and the poly-dispersity index (PDI) was 0.18. The binding yield of WGA to CS-NPs was comprised between 27.8% and 87.9% depending mostly on the addition of 0.3% (w/v) glutaraldehyde solution. A competitive inhibition experiment of WGA-CS-NPs to bovine submaxillary gland mucin (BSM) was taken to illuminate the binding activity of WGA-CS-NPs to the sugar of N-acetylglucosamine. After the addition of NAG, the binding rates between CS-NPs and BSM almost didn't change, while the binding rates between WGA-CS-NPs and BSM dropped down significantly, which confirmed the specific binding characteristics of WGA to NAG.
Acetylglucosamine ; chemistry ; metabolism ; Chitosan ; chemistry ; metabolism ; Drug Delivery Systems ; Mucins ; metabolism ; Nanoparticles ; Particle Size ; Protein Binding ; Wheat Germ Agglutinins ; chemistry ; metabolism

O-linked N-acetylglucosamine (O-GlcNAc) represents a key regulatory post-translational modification (PTM) that is reversible and often reciprocal with phosphorylation of serine and threonine at the same or nearby residues. Although recent technical advances in O-GlcNAc site-mapping methods combined with mass spectrometry (MS) techniques have facilitated study of the fundamental roles of O-GlcNAcylation in cellular processes, an efficient technique for examining the dynamic, reciprocal relationships between O-GlcNAcylation and phosphorylation is needed to provide greater insights into the regulatory functions of O-GlcNAcylation. Here, we describe a strategy for selectively identifying both O-GlcNAc- and phospho-modified sites. This strategy involves metal affinity separation of O-GlcNAcylated and phosphorylated peptides, beta-elimination of O-GlcNAcyl or phosphoryl functional groups from the separated peptides followed by dithiothreitol (DTT) conjugation (BEMAD), affinity purification of DTT-conjugated peptides using thiol affinity chromatography, and identification of formerly O-GlcNAcylated or phosphorylated peptides by MS. The combined metal affinity separation and BEMAD approach allows selective enrichment of O-GlcNAcylated peptides over phosphorylated counterparts. Using this approach with mouse brain synaptosomes, we identified the serine residue at 605 of the synapsin-1 peptide, 603QASQAGPGPR612, and the serine residue at 692 of the tau peptide, 688SPVVSGDTSPR698, which were found to be potential reciprocal O-GlcNAcylation and phosphorylation sites. These results demonstrate that our strategy enables mapping of the reciprocal site occupancy of O-GlcNAcylation and phosphorylation of proteins, which permits the assessment of cross-talk between these two PTMs and their regulatory roles.
Acetylglucosamine/*metabolism ; Amino Acid Sequence ; Animals ; Brain/*metabolism ; Chromatography, Affinity ; Glycosylation ; Mice ; Molecular Sequence Data ; Peptides/isolation & purification ; Phosphorylation ; Synapsins/chemistry/*metabolism ; Synaptosomes/*metabolism ; Tandem Mass Spectrometry ; tau Proteins/chemistry/*metabolism

It has been known that O-linked beta-N-acetylglucosamine (O-GlcNAc) modification of proteins plays an important role in transcription, translation, nuclear transport and signal transduction. The increased flux of glucose through the hexosamine biosynthetic pathway (HBP) and increased O-GlcNAc modification of protein have been suggested as one of the causes in the development of insulin resistance. However, it is not clear at the molecular level, how O-GlcNAc protein modification results in substantial impairment of insulin signaling. To clarify the association of O-GlcNAc protein modification and insulin resistance in rat primary adipocytes, we treated the adipocytes with O-(2-acetamido-2deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc), a potent inhibitor of O-GlcNAcase that catalyzes removal of O-GlcNAc from proteins. Prolonged treatment of PUGNAc (100 micrometer for 12 h) increased O-GlcNAc modification on proteins in adipocytes. PUGNAc also drastically decreased insulin-stimulated 2-deoxyglucose (2DG) uptake and GLUT4 translocation in adipocytes, indicating that PUGNAc developed impaired glucose utilization and insulin resistance in adipocytes. Interestingly, the O-GlcNAc modification of IRS-1 and Akt2 was increased by PUGNAc, accompanied by a partial reduction of insulin-stimulated phosphorylations of IRS-1 and Akt2. The PUGNAc treatment has no effect on the expression level of GLUT4, whereas O-GlcNAc modification of GLUT4 was increased. These results suggest that the increase of O-GlcNAc modification on insulin signal pathway intermediates, such as IRS-1 and Akt2, reduces the insulin-stimulated phosphorylation of IRS-1 and Akt2, subsequently leading to insulin resistance in rat primary adipocytes.
Acetylglucosamine/*analogs & derivatives/metabolism/pharmacology ; Adipocytes/*metabolism ; Animals ; Deoxyglucose/pharmacokinetics ; Glycosylation ; Immunoprecipitation ; *Insulin Resistance ; Male ; Monosaccharide Transport Proteins/metabolism ; Oximes/*pharmacology ; Phenylcarbamates/*pharmacology ; Phosphoproteins/*metabolism ; Phosphorylation ; Protein-Serine-Threonine Kinases/*metabolism ; Proto-Oncogene Proteins/*metabolism ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Subcellular Fractions/metabolism ; beta-N-Acetylhexosaminidase/antagonists & inhibitors