Immune Suppression and Resistance Mediated by Constitutive Activation of Wnt/β-Catenin Signaling in Human Melanoma Cells

Cancer-induced immunosuppression is a major problem reducing antitumor effects of immunotherapies, but its molecular mechanism has not been well understood. We evaluated immunosuppressive roles of activated Wnt/β-catenin pathways in human melanoma for dendritic cells (DCs) and CTLs. IL-10 expression was associated with β-catenin accumulation in human melanoma cell lines and tissues and was induced by direct β-catenin/TCF binding to the IL-10 promoter. Culture supernatants from β-catenin-accumulated melanoma have activities to impair DC maturation and to induce possible regulatory DCs. Those immunosuppressive culture supernatant activities were reduced by knocking down β-catenin in melanoma cells, partly owing to downregulation of IL-10. Murine splenic and tumor-infiltrating DCs obtained from nude mice implanted with human mutant β-catenin-overexpressed melanoma cells had less ability to activate T cells than did DCs from mice with control melanoma cells, showing in vivo suppression of DCs by activated Wnt/β-catenin signaling in human melanoma. This in vivo DC suppression was restored by the administration of a β-catenin inhibitor, PKF115-584. β-catenin-overexpressed melanoma inhibited IFN-γ production by melanoma-specific CTLs in an IL-10-independent manner and is more resistant to CTL lysis in vitro and in vivo. These results indicate that Wnt/β-catenin pathways in human melanoma may be involved in immunosuppression and immunoresistance in both induction and effector phases of antitumor immunoresponses partly through IL-10 production, and they may be attractive targets for restoring immunocompetence in patients with Wnt/β-catenin-activated melanoma.     

Plasma lipid profiling across species for the identification of optimal animal models of human dyslipidemia

In an attempt to understand the applicability of various animal models to dyslipidemia in humans and to identify improved preclinical models for target discovery and validation for dyslipidemia, we measured comprehensive plasma lipid profiles in 24 models. These included five mouse strains, six other nonprimate species, and four nonhuman primate (NHP) species, and both healthy animals and animals with metabolic disorders. Dyslipidemic humans were assessed by the same measures. Plasma lipoprotein profiles, eight major plasma lipid fractions, and FA compositions within these lipid fractions were compared both qualitatively and quantitatively across the species. Given the importance of statins in decreasing plasma low-density lipoprotein cholesterol for treatment of dyslipidemia in humans, the responses of these measures to simvastatin treatment were also assessed for each species and compared with dyslipidemic humans. NHPs, followed by dog, were the models that demonstrated closest overall match to dyslipidemic humans. For the subset of the dyslipidemic population with high plasma triglyceride levels, the data also pointed to hamster and db/db mouse as representative models for practical use in target validation. Most traditional models, including rabbit, Zucker diabetic fatty rat, and the majority of mouse models, did not demonstrate overall similarity to dyslipidemic humans in this study.     

Gain of function by phosphorylation in Presenilin 1-mediated regulation of insulin signaling

During pregnancy, activation of the maternal immune system results in inflammation in the foetal nervous system. The causative agents are pro-inflammatory cytokines like interleukin-1β (IL-1β), produced by the foetus. In this study, we examine the effect of IL-1β on the proliferation and differentiation of neural progenitor cells (NPCs) to better understand its potential effects on the developing brain. We find that the IL-1β receptor (IL-1R1) is expressed in the ventral mesencephalon of the developing brain. Furthermore, IL-1R1 is expressed on Nestin-positive, Sox-2-positive NPCs. IL-1β treatment reduced the numbers of proliferating NPCs, an effect prevented by the IL-1R1 receptor antagonist. LDH and MTT assays, and western blot analysis for cleaved caspase 3 and poly(ADP-ribose) polymerase, confirmed that this was not due to an increase in cell death but rather an induction of differentiation. To further study the effects of IL-1β on cell fate determination, we differentiated NPCs in the presence and absence of IL-1β. Il-1β promoted gliogenesis and inhibited neurogenesis, an effect that required p38-MAPK kinase signalling. In summary, these data show that exposure of NPCs to IL-1β affects their development. This necessitates an examination of the consequences that maternal immune system activation during pregnancy has on the cellular architecture of the developing brain.     

Generation of HIV latency in humanized BLT mice

Here we demonstrate that a combination of tenofovir, emtricitabine, and raltegravir effectively suppresses peripheral and systemic HIV replication in humanized BLT mice. We also demonstrate that antiretroviral therapy (ART)-treated humanized BLT mice harbor latently infected resting human CD4+ T cells that can be induced ex vivo to produce HIV. We observed that the levels of infected resting human CD4+ T cells present in BLT mice are within the range of those observed circulating in patients undergoing suppressive ART. These results demonstrate the potential of humanized BLT mice as an attractive model for testing the in vivo efficacy of novel HIV eradication strategies.     

Intermediate frequency magnetic field at 23 kHz does not modify gene expression in human fetus‐derived astroglia cells

The increased use of induction heating (IH) cooktops in Japan and Europe has raised public concern on potential health effects of the magnetic fields generated by IH cooktops. In this study, we evaluated the effects of intermediate frequency (IF) magnetic fields generated by IH cooktops on gene expression profiles. Human fetus‐derived astroglia cells were exposed to magnetic fields at 23 kHz and 100 µT_rms for 2, 4, and 6 h and gene expression profiles in cells were assessed using cDNA microarray. There were no detectable effects of the IF magnetic fields at 23 kHz on the gene expression profile, whereas the heat treatment at 43 °C for 2 h, as a positive control, affected gene expression including inducing heat shock proteins. Principal component analysis and hierarchical analysis showed that the gene profiles of IF‐exposed groups were similar to the sham‐exposed group and were different than the heat treatment group. These results demonstrated that exposure of human fetus‐derived astroglia cells to an IF magnetic field at 23 kHz and 100 µT_rms for up to 6 h did not induce detectable changes in gene expression profile. Bioelectromagnetics 33:662–669, 2012. © 2012 Wiley Periodicals, Inc.     

Temporal variation in chum salmon, Oncorhynchus keta, diets in the central Bering Sea in summer and early autumn

Seasonal, ontogenetic, and diel variations in the diets of chum salmon, Oncorhynchus keta, were examined by analyzing the stomach contents of 1398 fish (300–755 mm fork length) collected in the Bering Sea during summer and early autumn of 2002. Whereas mesozooplankton, including euphausiids, hyperiids, and gastropods, constituted the greatest portion of the stomach contents during the summer, forage fishes (Stenobrachius leucopsarus and Atka mackerel, Pleurogrammus monopterygius) were the most important items during early autumn. Although no apparent diel trend was found in feeding intensity, distinct diel differences in prey composition were observed. Chum salmon caught in the morning contained Stenobrachius leucopsarus, whereas those caught in the afternoon had mainly fed on euphausiids. Thus, chum salmon diets change temporally because of changes in prey availability that result from differences in the annual life cycles and diurnal vertical migrations of prey species.     

The fate of mycotoxins during the distillation process of barley shochu, a distilled alcoholic beverage

Mycotoxins are frequent contaminants of grains and critical risk substances for brewers. Fermented barley mash contaminated artificially with 13 representative mycotoxins was distilled with small-scale apparatuses to elucidate the possibility of mycotoxin transfer from mash to distillates. None of these were detected in the distillates. The distillation process can effectively reduce the contamination risk posed by mycotoxins in distilled alcoholic beverages.     

Construction of a metagenomic library for the marine sponge Halichondria okadai

Symbionts of the marine sponge Halichondria okadai are promising as a source of natural products. Metagenomic technology is a powerful tool for accessing the genetic and biochemical potential of bacteria. Hence, we established a method of recovering bacterial-enriched metagenomic DNA by stepwise centrifugation. The metagenomic DNA was analyzed by ultrafast 454-pyrosequencing technology, and the results suggested that more than three types of bacterial DNA, Alphaproteobacteria, Actinobacteria, and Cyanobacteria, had been recovered, and that eukaryotic genes comprised only 0.02% of the metagenomic DNA. These results indicate that stepwise centrifugation and real-time quantitative PCR were effective for separating sponge cells and symbiotic bacteria, and that we constructed a bacteria-enriched metagenomic library from a marine sponge, H. okadai, selectively for the first time.     

Conditional deletion of Tgfbr2 in hypertrophic chondrocytes delays terminal chondrocyte differentiation

Transforming growth factor β (Tgfb) signaling plays an important role in endochondral ossification. Previous studies of mice in which the Tgfb type II receptor gene (Tgfbr2) was deleted in the limb bud mesenchymal cells or differentiated chondrocytes showed defects in the development of the long bones or the axial skeleton, respectively. Here, we generated mouse embryos in which the Tgfbr2 gene was ablated in hypertrophic chondrocytes. These mice exhibited delays in both the hypertrophic conversion of proliferating chondrocytes and the subsequent terminal chondrocyte differentiation. The expression domains of Col10a1, Matrix metalloproteinase 13, and Osteopontin were small, and the expression of Vascular endothelial growth factor and Platelet endothelial cell adhesion molecule was downregulated. The calcification of the bone collar in the mutant mice was markedly delayed and the periosteum was thin, possibly because of the downregulation of Indian hedgehog expression. We conclude that Tgfb signaling in hypertrophic chondrocytes positively regulates terminal chondrocyte differentiation, angiogenesis in calcified cartilage, and osteogenesis in the bone collar, at least partly through Indian hedgehog signaling in vivo.     

Effects on Lignin Structure of Coumarate 3-Hydroxylase Downregulation in Poplar

The lignin structural ramifications of coumarate 3-hydroxylase (C3H) downregulation have not been addressed in hardwoods. Such information is required to accompany an assessment of the digestibility and bioenergy performance characteristics of poplar, in particular. Structurally rich 2D NMR methods were applied to the entire lignin fraction to delineate lignin p-hydroxyphenyl:guaiacyl:syringyl (H:G:S) levels and linkage distribution changes (and to compare with traditional degradative analyses). C3H downregulation reduced lignin levels by half and markedly increased the proportion of H units relative to the normally dominant G and S units. Relative stem H unit levels were up by ???100-fold to ???31?%, almost totally at the expense of G units; differences in the lignin interunit linkage distributions were more subtle. The H level in the most drastically C3H-downregulated transgenic poplar falls well beyond the H:G:S compositional bounds of normal angiosperms. The response observed here, in poplar, differs markedly from that reported for alfalfa where the S:G ratio remained almost constant even at substantial H levels, highlighting the often differing responses among plant species.