Improvement of cognitive function in Alzheimer's disease model mice by genetic and pharmacological inhibition of the EP(4) receptor

Amyloid-β peptide (Aβ), which is generated by the β- and γ-secretase-mediated proteolysis of β-amyloid precursor protein (APP), plays an important role in the pathogenesis of Alzheimer's disease (AD). We recently reported that prostaglandin E(2) (PGE(2) ) stimulates the production of Aβ through both EP(2) and EP(4) receptors and that activation of the EP(4) receptor stimulates Aβ production through endocytosis and activation of γ-secretase. We here found that transgenic mice expressing mutant APP (APP23) mice showed a greater or lesser apparent cognitive deficit when they were crossed with mice lacking EP(2) or EP(4) receptors, respectively. Mice lacking the EP(4) receptor also displayed lower levels of Aβ plaque deposition and less neuronal and synaptic loss than control mice. Oral administration of a specific EP(4) receptor antagonist, AE3-208 to APP23 mice, improved their cognitive performance, as well as decreasing brain levels of Aβ and suppressing endocytosis and activation of γ-secretase. Taken together, these results suggest that inhibition of the EP(4) receptor improves the cognitive function of APP23 mice by suppressing Aβ production and reducing neuronal and synaptic loss. We therefore propose that EP(4) receptor antagonists, such as AE3-208, could be therapeutically beneficial for the prevention and treatment of AD.     

Cultivation of microalgae in the solution from the desalting process of soy sauce waste treatment and utilization of the algal biomass for ethanol fermentation

The growth of four marine microalgae was examined in a medium prepared from the effluent from the desalting process of soy sauce waste. A strain of Dunaliella that showed abundant growth on soy sauce waste extract was selected, and optimum cultivation conditions were determined. The algal cells produced were disrupted, and saccharified with glucoamylase. The saccharified solution was fermented using Saccharomyces cerevisiae IAM 4140. Stoichiometric study revealed that 11mg of ethanol was produced from 1g (dry cell weight) of Dunaliella cells. This work indicates a new method for removing waste products of the soy sauce production industry.     

Equilibrium study on the binding between thermolysin and Streptomyces metalloprotease inhibitor, talopeptin (MKI)

The binding between thermolysin and its specific inhibitor, talopeptin (MKI), was found to show a fluorescence increase when excited at 280 nm and 295 nm, and a difference spectrum characterized by two peaks at 294 nm and 285 nm with a shoulder around 278 nm, indicating a microenvironmental change in tryptophan residue(s) of thermolysin and/or talopeptin. The inhibitor constant of talopeptin against thermolysin, Ki, was determined over the pH range 5-9 from the inhibition of the enzyme activity towards 3-(2-furylacryloyl)-glycyl-L-leucine amide (FAGLA) as a substrate. The dissociation constant of thermolysin-talopeptin complex, Kd, determined directly from fluorometric titration was in good agreement with the inhibitor constant, Ki, between pH 6 and 8.5. The pH dependence of Ki and Kd suggested that at least two ionizable groups of thermolysin in their protonated forms are essential for the binding between thermolysin and talopeptin. The temperature dependence of K1 at pH 5.5 indicated that the binding is largely exothermic (delta H degree = -12 kcal/mol) and essentially enthalpy-driven.     

Substrate specificity of thePenicillium lilacinum enzyme lytic to the cell wall ofRhodotorula glutinis and the structure of theRhodotorula cell wall glucomannan

The lytic enzyme active on cell walls ofRhodotorula, which was produced byPenicillium lilacinum ATCC 36010, decomposed an extracellular mannan fromRhodotorula glutinis IFO 0695 and was confined to the β-1,3-mannoside bond on the reducing side of the β-1,4-linkedd-mannopyranose. Based on these results, the structure of the glucomannan, which was a major component ofRhodotorula cell walls, was proposed.     

Purification and properties of a proteinaceous metallo-proteinase inhibitor from Streptomyces nigrescens TK-23.

A novel metallo-proteinase inhibitor which is capable of inhibiting the activities of metallo-proteinases such as the thermolysin, was isolated from the culture filtrates of Streptomyces nigrescens TK-23. The inhibitor was purified batch-wise from the culture filtrate by Amberlite IRC-50 and column chromatographies on CM-Sephadex C-50 and Sephadex G-50. The purified inhibitor showed a single band on 15% polyacrylamide gel electrophoresis at pH 4.3, and at pH 7.5 on SDS-gels. The inhibitor retained 80% of its original activity after treatment of 100 degrees C for 5 min between pH and 7. The molecular weight was estimated to be 12 000 by gel filtration and SDS-polyacrylamide gel electrophoresis, and calcuated as 11 950 from its amino acid composition. The isoelectric point was pH 10.3. The inhibitor showed a high content of hydrophobic amino acids, did not contain tryptophan, and had two disulfide bridges. It also showed specific inhibitory activity for metallo-proteinases but not for serine-, thio- and carboxyl-proteinases.     

5-(carboxymethylaminomethyl)-2-thiouridine, a new modified nucleoside found at the first letter position of the anticodon.

The structure of a modified uridine derivative which was detected at the first letter position of the anticodon of Bacillus subtilis tRNA1Lys was determined to be 5-(carboxymethylaminomethyl)-2-thiouridine. The determination was mainly based in this ultraviolet absorption spectra and mass spectrometric analysis of the trimethylsilyl derivative.     

Rare sugar d-psicose improves insulin sensitivity and glucose tolerance in type 2 diabetes Otsuka Long-Evans Tokushima Fatty (OLETF) rats

A rare sugar, d-psicose has progressively been evaluated as a unique metabolic regulator of glucose and lipid metabolism, and thus represents a promising compound for the treatment of type 2 diabetes mellitus (T2DM). The present study was undertaken to examine the underlying effector organs of d-psicose in lowering blood glucose and abdominal fat by exploiting a T2DM rat model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Rats were fed 5% d-psicose or 5% d-glucose supplemented in drinking water, and only water in the control for 13 weeks and the protective effects were compared. A non-diabetic Long-Evans Tokushima Otsuka (LETO), fed with water served as a counter control of OLETF. After 13 weeks feeding, d-psicose treatment significantly reduced the increase in body weight and abdominal fat mass. Oral glucose tolerance test (OGTT) showed the reduced blood glucose and insulin levels suggesting the improvement of insulin resistance in OLETF rats. Oil-red-O staining elucidated that d-psicose significantly reduced lipid accumulation in the liver. Immunohistochemical analysis showed d-psicose induced glucokinase translocation from nucleus to cytoplasm of the liver which enhances glucokinase activity and subsequent synthesis of glycogen in the liver. d-psicose also protected the pathological change of the β-cells of pancreatic islets. These data demonstrate that d-psicose controls blood glucose levels by reducing lipotoxicity in liver and by preserving pancreatic β-cell function.     

Chronic Restraint Stress Inhibits Hair Growth via Substance P Mediated by Reactive Oxygen Species in Mice

Backgrounds

Solid evidence has demonstrated that psychoemotional stress induced alteration of hair cycle through neuropeptide substance P (SP) mediated immune response, the role of reactive oxygen species (ROS) in brain-skin-axis regulation system remains unknown.

Objectives

The present study aims to investigate possible mechanisms of ROS in regulation of SP-mast cell signal pathway in chronic restraint stress (CRS, a model of chronic psychoemotional stress) which induced abnormal of hair cycle.

Methods and Results

Our results have demonstrated that CRS actually altered hair cycle by inhibiting hair follicle growth in vivo, prolonging the telogen stage and delaying subsequent anagen and catagen stage. Up-regulation of SP protein expression in cutaneous peripheral nerve fibers and activation of mast cell were observed accompanied with increase of lipid peroxidation levels and reduction of the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in CRS mice skin. In addition, SP receptor antagonist (RP67580) reduced mast cell activations and lipid peroxidation levels as well as increased GSH-Px activity and normalized hair cycle. Furthermore, antioxidant Tempol (a free radical scavenger) also restored hair cycle, reduced SP protein expression and mast cell activation.

Conclusions

Our study provides the first solid evidence for how ROS play a role in regulation of psychoemotional stress induced SP-Mast cell pathway which may provide a convincing rationale for antioxidant application in clinical treatment with psychological stress induced hair loss.