Insulin-like growth factor-I induces androgen receptor activation in differentiating C2C12 skeletal muscle cells

The modulating effect of IGF-I on the regulation of AR gene expression and activation in skeletal muscle cells remains poorly understood. In this study, the effects of IGF-I treatment on AR induction and activation in the absence of AR ligands were examined. Differentiating C2C12 cells were treated with different concentrations (0–250 ng/ml) of IGF-I or for various periods of time (0–60 min) of 250 ng/ml IGF-I. Treatment of C2C12 cells with IGF-I resulted in a dose- and time-dependent increase in total AR and phosphorylated AR (Ser 213). IGF-I treatment also led to significantly increased AR mRNA expression when compared with the control. The levels of skeletal α-actin and myogenin mRNA, known target genes of AR, were also significantly upregulated after 5 or 10 min of treatment with IGF-I. Confocal images revealed that IGF-I stimulated nuclear localization of AR in the absence of ligands. In addition, an electrophoretic mobility shift assay indicated that IGF-I stimulated the AR DNA binding activity in a time-dependent manner. The present results suggest that IGF-I stimulates the expression and activation of AR by ligand-independent mechanism in differentiating C2C12 mouse skeletal muscle cells.     

Impact of buffering hypercapnic acidosis on cell wounding in ventilator-injured rat lungs

We measured the effects of raising perfusate pH on ventilator-induced cell wounding and repair in ex vivo mechanically ventilated hypercapnic rat lungs. Lungs were randomized to one of three perfusate groups: 1) unbuffered hypercapnic acidosis, 2) bicarbonate-buffered hypercapnia, or 3) tris-hydroxymethyl aminomethane (THAM)-buffered hypercapnia. The membrane-impermeant label propidium iodide was added to the perfusate either during or after injurious ventilation providing a means to subsequently identify transiently wounded and permanently wounded cells in optical sections of subpleural alveoli. Normalizing perfusate pH in hypercapnic preparations attenuated ventilator-induced cell injury, particularly in THAM-buffered preparations. This was observed despite greater amounts of edema and impaired lung mechanics compared with other treatment groups. Protective effects of buffering of hypercapnic acidosis on injury and repair were subsequently confirmed in a cell scratch model. We conclude that buffering of hypercapnic acidosis attenuates plasma cell injury induced by mechanical hyperinflation.     

Adjuvant effect of bovine heat shock protein 70 on piroplasm surface protein, p33, of Theileria sergenti

In this study, we investigated the immunological effects of bovine heat shock protein 70 (HSP70) on the major Theileria sergenti surface protein (p33).The gene encoding p33 was expressed as a fusion protein with bovine HSP70 from a plasmid vector. The adjuvant function of HSP70 on p33 was evaluated with regard to antibody response, cytokine production, and a challenge experiment in mice or cattle. HSP-p33 fusion protein provoked higher humoral and cellular immunity than either Escherichia coli-expressed p33 or piroplasm soluble protein. The HSP adjuvant activity toward p33 was also possible to detect in the inoculated cattle. The overall growth of parasites in cattle was significantly restrained in the HSP-p33-inoculated group, up to 50–52 days longer than in the controls.The present results indicate that HSP-p33 fusion protein is a promising candidate vaccine for clinical theileriosis in the field.     

Responses from freshwater sediment during electricity generation using microbial fuel cells

In a two-electrode system, freshwater sediment was used as a fuel to examine the relationship between current generation and organic matter consumption with different types of electrode. Sediment microbial fuel cells using porous electrodes showed a superior performance in terms of generating current when compared with the use of non-porous electrodes. The maximum current densities with thicker and thin porous electrodes were 45.4 and 37.6 mA m⁻², respectively, whereas the value with non-porous electrodes was 13.9 mA m⁻². The amount of organic matter removed correlated with the current produced. The redox potential in the anode area under closed-circuit conditions was +246.3 ± 67.7 mV, while that under open-circuit conditions only reached −143.0 ± 7.18 mV. This suggests that an application of this system in organic-rich sediment could provide environmental benefits such as decreasing organic matter and prohibiting methane emission in conjunction with electricity production via an anaerobic oxidation process.     

Variations in mass transfer to single endothelial cells

Mass transfer between flowing blood and arterial mural cells (including vascular endothelial cells) may play an important role in atherogenesis. Endothelial cells are known to have an apical surface topography that is not flat, and hence mass transfer patterns to individual endothelial cells are likely affected by the local cellular topography. The purpose of this paper is to investigate the relationship between vascular endothelial cell surface topography and cellular level mass transfer. Confluent porcine endothelial monolayers were cultured under both shear and static conditions and atomic force microscopy was used to measure endothelial cell topography. Using finite element methods and the measured cell topography, flow and concentration fields were calculated for a typical, small, blood-borne solute. A relative Sherwood number was defined as the difference between the computed Sherwood number and that predicted by the Leveque solution for mass transfer over a flat surface: this eliminates the effects of axial location on mass transfer efficiency. The average intracellular relative Sherwood number range was found to be dependent on cell height and not dependent on cell elongation due to shear stress in culture. The mass flux to individual cells reached a maximum at the highest point on the endothelial cell surface, typically corresponding to the nucleus of the cell. Therefore, for small receptor-mediated solutes, increased solute uptake efficiency can be achieved by concentrating receptors near the nucleus. The main conclusion of the work is that although the rate of mass transfer varies greatly over an individual cell, the average mass transfer rate to a cell is close to that predicted for a flat cell. In comparison to other hemodynamic factors, the topography of endothelial cells therefore seems to have little effect on mass transfer rates and is likely physiologically insignificant.     

Enhancement of pheochromocytoma nerve cell growth by consecutive fractionization of <Emphasis Type="Italic">Angelica gigas</Emphasis> Nakai extracts

This work was to investigate the effect of flavonoids from Angelica gigas Nakai on the proliferation and differentiation of PC12 cells. Several solvents including hexane, chloroform, ethyl acetate, butanol and water consecutively partitioned. We determined the ethanol crude extract of Angelica gigas Nakai. The hexane fraction was shown to contain the highest number of flavonoids as follows; 21.48 mg/g and the composition of the flavonoids was as follows: 12.24 mg/g of quercetin, 4.39 mg/g of myricetin and 2.58 mg/g of catechin. In addition, this hexane fraction greatly increased both cell growth and outgrowth of the neurite, and whose effects were three times higher than those of the other fractions. The length of the neurites was measured as ca. 110 μm in adding 50 μg/mL of the hexane fraction, which was about the same as the case of adding 50 ng/mL of NGF as a positive control. This result indicates that the differentiation of PC12 cells by the addition of the hexane fraction was comparable to the case of adding NGF. The hexane fraction was also determined to prevent apoptosis of PC12 cells by suppressing DNA fragmentation. It is interesting that the mixture of three major flavonoids, quercetin, myricetin and catechin showed stronger activity on, both PC12 cell growth and neuritis outgrowth, than when adding each flavonoid alone. We believe this was due to the synergistic effects of the three flavonoids. The activities of these flavonoids from Angelica gigas Nakai are reported for the first time in this study.     

Cocoa polyphenols attenuate hydrogen peroxide-induced inhibition of gap-junction intercellular communication by blocking phosphorylation of connexin 43 via the MEK/ERK signaling pathway

Cocoa, a good source of dietary antioxidative polyphenols, exhibited anticarcinogenic activity in animal models, but the molecular mechanisms of the chemopreventive potential of cocoa remain unclear. Inhibition of gap-junction intercellular communication (GJIC) is strongly related to tumorigenesis. Cocoa polyphenol extracts (CPE) dose dependently attenuated hydrogen peroxide (H₂O₂)-induced inhibition of GJIC in rat liver epithelial (RLE) cells. CPE inhibited the H₂O₂-induced phosphorylation and internalization of connexin 43, which is a regulating protein of GJIC in RLE cells. The H₂O₂-induced accumulation of reactive oxygen species and activation of extracellular signal-regulated kinase were inhibited by CPE treatment. However, CPE did not block H₂O₂-induced phosphorylation of p38 mitogen-activated protein kinase. An ex vivo kinase assay demonstrated that CPE inhibited the H₂O₂-induced mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) 1 activity in RLE cell lysates. Ex vivo pull-down assay data revealed that CPE directly bound with MEK1 to inhibit MEK1 activity. These results indicate that CPE protects against the H₂O₂-induced inhibition of GJIC through antioxidant activity and direct inhibition of MEK activity, which may contribute to its chemopreventive potential.     

Metformin Normalizes Type 2 Diabetes-Induced Decrease in Cell Proliferation and Neuroblast Differentiation in the Rat Dentate Gyrus

In this study, we observed the effects of metformin, one of the most widely prescribed drugs for the treatment of type 2 diabetes, on cell proliferation and neuroblast differentiation in the subgranular zone of the hippocampal dentate gyrus (SZDG) in Zucker diabetic fatty (ZDF) rats, which are a model for type 2 diabetes. For this, metformin was administered orally once a day to 14-week-old ZDF rats for 2 weeks and the animals were sacrificed at 16 weeks of age. During this period, blood glucose levels were higher in the vehicle-treated ZDF rats than in the Zucker lean control (ZLC) rats. Metformin treatment significantly decreased the blood glucose levels from 15.5 weeks of age. In the SZDG, Ki67 (a marker for cell proliferation)- and doublecortin (DCX, a marker for differentiated neuroblasts)-immunoreactive cells were much lower in the vehicle-treated ZDF rats than in the ZLC rats. In the metformin-treated ZDF group, Ki67- and DCX-immunoreactive cells were significantly increased in the SZDG compared to those in the vehicle-treated ZDF group. These results suggest that diabetes significantly reduces cell proliferation and neuroblast differentiation in the SZDG and that metformin treatment normalizes the reduction of cell proliferation and neuroblast differentiation in the SZDG in diabetic rats.     

Oncostatin M induces dendritic cell maturation and Th1 polarization

Oncostatin M (OSM) is a pleiotropic cytokine and a member of the gp130/IL-6 cytokine family that has been found to be involved in both pro- and anti-inflammatory responses in cell-mediated immunity. Maturation of dendritic cells (DCs) is crucial for initiation of primary immune responses and is regulated by several stimuli. In this study, the role of OSM in the phenotypic and functional maturation of DCs was evaluated in vitro. Stimulation with OSM upregulated the expression of CD80, CD86, MHC class I and MHC class II and reduced the endocytic capacity of immature DCs. Moreover, OSM induced the allogeneic immunostimulatory capacity of DCs by stimulating the production of the Th1-promoting cytokine IL-12. OSM also increased the production of IFN-γ by T cells in mixed-lymphocyte reactions, which would be expected to contribute to the Th1 polarization of the immune response. The expression of surface markers and cytokine production in DCs was mediated by both the MAPK and NF-κB pathways. Taken together, these results indicate that OSM may play a role in innate immunity and in acquired immunity by enhancing DCs maturation and promoting Th1 immune responses.