Regulation of dendritic excitability by activity-dependent trafficking of the A-type K+ channel subunit Kv4.2 in hippocampal neurons

Voltage-gated A-type K+ channel Kv4.2 subunits are highly expressed in the dendrites of hippocampal CA1 neurons. However, little is known about the subcellular distribution and trafficking of Kv4.2-containing channels. Here we provide evidence for activity-dependent trafficking of Kv4.2 in hippocampal spines and dendrites. Live imaging and electrophysiological recordings showed that Kv4.2 internalization is induced rapidly upon glutamate receptor stimulation. Kv4.2 internalization was clathrin mediated and required NMDA receptor activation and Ca2+ influx. In dissociated hippocampal neurons, mEPSC amplitude depended on functional Kv4.2 expression level and was enhanced by stimuli that induced Kv4.2 internalization. Long-term potentiation (LTP) induced by brief glycine application resulted in synaptic insertion of GluR1-containing AMPA receptors along with Kv4.2 internalization. We also found evidence of Kv4.2 internalization upon synaptically evoked LTP in CA1 neurons of hippocampal slice cultures. These results present an additional mechanism for synaptic integration and plasticity through the activity-dependent regulation of Kv4.2 channel surface expression.     

The suppressive effect of beta-glucan on the production of tumor necrosis factor-alpha in BV2 microglial cells

Beta-glucan was recently shown to have the ability to enhance and stimulate the immune system in humans, but little is known about its the anti-inflammatory effects. We investigated the effect of beta-glucan on the production of tumor necrosis factor-alpha (TNF-alpha), a major pro-inflammatory mediator, in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. beta-Glucan decreased the production and expression of TNF-alpha. In addition, it blocked LPS-stimulated activation of nuclear factor kappa B (NF-kappaB). Hence beta-glucan might suppress LPS-stimulated TNF-alpha production by inhibiting NF-kappaB in BV2 microglial cells.     

Anti-peptide antibody production elicited by in vitro immunization of human peripheral blood mononuclear cells

Human monoclonal antibodies have great potential for use in the treatment of various diseases. We have established an in vitro immunization protocol for inducing antigen-specific antibody production from human peripheral blood mononuclear cells (PBMCs). In the in vitro immunization protocol, PBMCs are pretreated with L-leucyl-L-leucine methyl ester (LLME) to remove suppressive cells, and are sensitized and cultured with a soluble antigen in the presence of IL-2, IL-4 and muramyl dipeptide for 8 d, and then an antigen-specific antibody is produced. In this study, we examined the novel possibility of an in vitro immunization protocol, specifically, whether LLME-treated PBMCs can be sensitized with a peptide antigen to produce an anti-peptide antibody. The results indicate that antigen-specific immune responses were elicited by a peptide antigen derived from rice allergen, a cholera toxin B subunit, and TNF-alpha as a sensitizing antigen in in vitro immunization. These results suggest that the in vitro immunization protocol is applicable in the generation of an anti-peptide antibody against various antigens, including food allergens, foreign antigens, and self-antigens.     

Ameliorative anti-diabetic activity of dangnyosoko, a Chinese herbal medicine, in diabetic rats

The preventive anti-diabetic effect of dangnyosoko (DNSK), a Chinese herbal medicine, was evaluated in STZ-induced diabetic rats. DNSK was orally administered once a day from 3 d after STZ-induction at 100, 200, and 500 mg/kg for 4 weeks, and the results were compared to those for glibenclamide. Dramatic decreases in body weight and plasma insulin levels and increases in blood and urine glucose levels were detected in STZ-induced diabetic animals with disruption and disappearance of pancreatic islets and increases in glucagon- and decreases in insulin-producing cells. However, these diabetic changes were significantly and dose-dependently inhibited by treatment with DNSK, and DNSK at 100 mg/kg showed more favorable effects than glibenclamide at 5 mg/kg. Based on these results, it is thought that DNSK has favorable effects in ameliorating changes in blood and urine glucose levels and body weight, and that histopathological changes in the pancreas in STZ induce diabetes.     

MSC-DC interactions: MSC inhibit maturation and migration of BM-derived DC

BACKGROUND: Mesenchymal stromal cells (MSC) comprise one of the BM stromal cells that are known to support hematopoiesis. It has also been suggested recently that MSC display immunosuppressive capacities through inhibiting the differentiation of monocyte-derived DC. DC travel to the lymph nodes (LN) to present Ag to T cells, and CCL21 is the chemokine that plays an important role in DC migration into the T-cell area of LN. We addressed the effect of MSC on this chemotactic activity of DC, one of the typical characteristics upon maturation. METHODS: BM cells were isolated and then cultured for generation of myeloid DC in the presence of GM-CSF and/or lipopolysaccharide with or without MSC. MSC were identified by flow cytometry of the immunologic markers and by performing colony-forming unit fibroblast assay. Migration of DC was observed with a newly developed time-lapse video microscopic technique. RESULTS: MSC co-culture inhibited the initial differentiation of DC, as well as their maturation. The matured DC actively migrated directionally in response to CCL21, a powerful DC-attracting chemokine, whereas the MSC co-cultured DC did not. DISCUSSION: Collectively, the findings of these experiments raise the possibility that MSC suppress the migratory function of DC and so they may serve immunoregulatory activities through the modulation of the Ag-presenting function of DC.     

Inferring biological functions and associated transcriptional regulators using gene set expression coherence analysis

Background  

Gene clustering has been widely used to group genes with similar expression pattern in microarray data analysis. Subsequent enrichment analysis using predefined gene sets can provide clues on which functional themes or regulatory sequence motifs are associated with individual gene clusters. In spite of the potential utility, gene clustering and enrichment analysis have been used in separate platforms, thus, the development of integrative algorithm linking both methods is highly challenging.     

Lipase-catalyzed acylation of naringin with palmitic acid in highly concentrated homogeneous solutions

Acylation reactions of naringin with palmitic acid were performed by a lipase after formation of highly concentrated homogeneous solutions. Their initial naringin concentration was 840–950 mM, which is 20–60 times greater than that in organic solvent media. The overall productivity of highly concentrated solutions was more than 15 times greater than those of organic phase media. The addition of DMSO (20–40%, w/w) to substrate mixtures lowered the melting temperature of a naringin–palmitic acid mixture (1:1 molar ratio) to about 40 °C. Reactions at 80 °C apparently followed Michaelis–Menten kinetics despite extremely high substrate concentrations. As the temperature increased from 60 °C to 80 °C, the apparent viscosity of the highly concentrated solution decreased remarkably from 4.31 Pa s to 0.063 Pa s. An activation energy of 7.65 kcal/mol obtained in a range of 60–75 °C suggests a diffusion-control. On the other hand, an activation energy of 17.09 kcal/mol in a range of 75–90 °C indicates a reaction-control. The highest product conversion yield of 33% (mol/mol) was obtained in a 10 h reaction at 80 °C. Addition of activated molecular sieves to the highly concentrated solution increased the product conversion yield by 7% (mol/mol), suggesting that the original equilibrium was disrupted by removing water and then a new equilibrium was reached.