Hexosamine-Induced TGF-ß Signaling and Osteogenic Differentiation of Dental Pulp Stem Cells Are Dependent on N-Acetylglucosaminyltransferase V.

Glycans of cell surface glycoproteins are involved in the regulation of cell migration, growth, and differentiation. N-acetyl-glucosaminyltransferase V (GnT-V) transfers N-acetyl-d-glucosamine to form ß1,6-branched N-glycans, thus playing a crucial role in the biosynthesis of glycoproteins. This study reveals the distinct expression of GnT-V in STRO-1 and CD-146 double-positive dental pulp stem cells (DPSCs). Furthermore, we investigated three types of hexosamines and their N-acetyl derivatives for possible effects on the osteogenic differentiation potential of DPSCs. Our results showed that exogenous d-glucosamine (GlcN), N-acetyl-d-glucosamine (GlcNAc), d-mannosamine (ManN), and acetyl-d-mannosamine (ManNAc) promoted DPSCs' early osteogenic differentiation in the absence of osteogenic supplements, but d-galactosamine (GalN) or N-acetyl-galactosamine (GalNAc) did not. Effects include the increased level of TGF-ß receptor type I, activation of TGF-ß signaling, and increased mRNA expression of osteogenic differentiation marker genes. The hexosamine-treated DPSCs showed an increased mineralized matrix deposition in the presence of osteogenic supplements. Moreover, the level of TGF-ß receptor type I and early osteogenic differentiation were abolished in the DPSCs transfected with siRNA for GnT-V knockdown. These results suggest that GnT-V plays a critical role in the hexosamine-induced activation of TGF-ß signaling and subsequent osteogenic differentiation of DPSCs.

ß-Phenylethylamine as a novel nutrient treatment to reduce bacterial contamination due to Escherichia coli O157:H7 on beef meat.

Bacterial infection by Escherichia coli O157:H7 through the consumption of beef meat or meat products is an ongoing problem, in part because bacteria develop resistances towards chemicals aimed at killing them. In an approach that uses bacterial nutrients to manipulate bacteria into behaviors or cellular phenotypes less harmful to humans, we screened a library of 95 carbon and 95 nitrogen sources for their effect on E. coli growth, cell division, and biofilm formation. In the initial screening experiment using the Phenotype MicroArray(TM) technology from BioLog (Hayward, CA), we narrowed the 190 starting nutrients down to eight which were consecutively tested as supplements in liquid beef broth medium. Acetoacetic acid (AAA) and ß-phenylethylamine (PEA) performed best in this experiment. On beef meat pieces, PEA reduced the bacterial cell count by 90% after incubation of the PEA treated and E. coli contaminated meat pieces at 10°C for one week.

[Animal model of distal myopathy with rimmed vacuoles/hereditary inclusion body myopathy and preclinical trial with sugar compounds].

Sialic acids are terminal sugars of glycolipids and glycoproteins and are involved in several cellular processes. Sialic acid biosynthesis occurs in the cytosol, where UDP-N-acetylglucosamine (GlcNAc) is sequentially converted to N-acetylmannosamine (ManNAc) 6-phosphate by UDP-GlcNAc-2-epimerase/ManNAc kinase enzymes, both of which are encoded by the GNE gene. Since the only existing mouse model of DMRV/hIBM (Gne(-/-)hGNED176VTg) exhibited decreased sialic acid levels in most organs, DMRV/hIBM is thought to be secondary to the metabolic defect in sialic acid production. Theoretically, replenishing sialic acid could be employed as a therapeutic option. It has been reported that N-acetylneuraminic acid (NeuAc) and ManNAc are well incorporated into cells and converted to sialic acid. Thus, we evaluated the efficacy and safety of ManNAc, NeuAc, and sialyllactose in the Gne(-/-)hGNED176VTg, by orally administering these agents to mice from 5-15 weeks continuously until they reached 54-57 weeks of age. The treatment showed beneficial effects in terms of survival rate, overall motor performance, myofiber size, ex vivo skeletal muscle contractile properties, and pathology. These low-dose compounds showed acceptable kidney and liver toxicity profiles. Thus our results show that the oral therapy with NeuAc and ManNAc or their derivatives is safe and effective in preventing myopathic symptoms in Gne(-/-)hGNED176VTg mice, and could be considered as a guide for further therapeutic trials.

Synthesis and pharmacokinetic and pharmacodynamic evaluation of the forodesine HCl analog BCX-3040.

Forodesine HCl is a potent inhibitor of the enzyme purine nucleoside phosphorylase (PNP) and is currently in clinical trials for the treatment of leukemia and lymphoma. Animal models indicated that forodesine HCl would have low oral bioavailability in humans and it was initially developed as an intravenous formulation. We were interested in identifying analogs of forodesine HCl with improved oral bioavailability. The 2'-deoxy analog (BCX-3040) was synthesized and its pharmacokinetic and pharmacodynamic properties compared with forodesine HCl.