Association of single-nucleotide polymorphisms in the suppressor of cytokine signaling 2 (SOCS2) gene with type 2 diabetes in the Japanese

Several previous linkage scans in type 2 diabetes (T2D) families indicated a putative susceptibility locus on chromosome 12q15-q22, while the underlying gene for T2D has not yet been identified. We performed a region-wide association analysis on 12q15-q22, using a dense set of >500 single-nucleotide polymorphisms (SNPs), in 1492 unrelated Japanese individuals enrolled in this study. We identified an association between T2D and a haplotype block spanning 13.6 kb of genomic DNA that includes the entire SOCS2 gene. Evolutionary-based haplotype analysis of haplotype-tagging SNPs followed by a "sliding window" haplotypic analysis indicated SNPs that mapped to the 5' region of the SOCS2gene to be associated with T2D with high statistical significance. The SOCS2 gene was expressed ubiquitously in human and murine tissues, including pancreatic beta-cell lines. Adenovirus-mediated expression of the SOCS2 gene in MIN6 cells or isolated rat islets significantly suppressed glucose-stimulated insulin secretion. Our data indicate that SOCS2 may play a role in susceptibility to T2D in the Japanese.     

Development of urine glucose meter based on micro-planer amperometric biosensor and its clinical application for self-monitoring of urine glucose

The highly sensitive urine glucose meter based on amperometric glucose sensor was developed and commercialized. It shows remarkable performances of wide measurement range in 0-2000 mgdl(-1), rapid response time as 6s and robustness against influence by interferents like ascorbic acid or acetaminophen. Correlation between the developed urine glucose meter and commercialized clinical-use urine glucose analyzer showed excellent linear relationship. The monitoring of postmeal blood glucose levels by assess of urine glucose of actual subjects was performed with the developed urine glucose meter. The experimental results suggest the urine glucose level 120 min following the meal should be the appropriate index for diabetes or impaired glucose tolerance to control blood glucose level. The new portable meter was developed, and is expected for flexible use at places other than home or office.     

Fluorescence-based optimization of human bitter taste receptor expression in Saccharomyces cerevisiae

Human TAS2 receptors (hTAS2Rs) perceive bitter tastants, but few studies have explored the structure-function relationships of these receptors. In this paper, we report our trials on the large-scale preparations of hTAS2Rs for structural analysis. Twenty-five hTAS2Rs were expressed using a GFP-fusion yeast system in which the constructs and the culture conditions (e.g., the signal sequence, incubation time and temperature after induction) were optimized by measuring GFP fluorescence. After optimization, five hTAS2Rs (hTAS2R7, hTAS2R8, hTAS2R16, hTAS2R41, and hTAS2R48) were expressed at levels greater than 1 mg protein/L of culture, which is a preferable level for purification and crystallization. Among these five bitter taste receptors, hTAS2R41 exhibited the highest detergent solubilization efficiency of 87.1% in n-dodecyl-β-d-maltopyranoside (DDM)/cholesteryl hemisuccinate (CHS). Fluorescence size-exclusion chromatography showed that hTAS2R41 exhibited monodispersity in DDM/CHS without aggregates, suggesting that hTAS2R41 is a good target for future crystallization trials.     

Comprehensive Analysis of Inflammatory Immune Mediators in Vitreoretinal Diseases

Inflammation affects the formation and the progression of various vitreoretinal diseases. We performed a comprehensive analysis of inflammatory immune mediators in the vitreous fluids from total of 345 patients with diabetic macular edema (DME, n = 92), proliferative diabetic retinopathy (PDR, n = 147), branch retinal vein occlusion (BRVO, n = 30), central retinal vein occlusion (CRVO, n = 13) and rhegmatogenous retinal detachment (RRD, n = 63). As a control, we selected a total of 83 patients with either idiopathic macular hole (MH) or idiopathic epiretinal membrane (ERM) that were free of major pathogenic intraocular changes, such as ischemic retina and proliferative membranes. The concentrations of 20 soluble factors (nine cytokines, six chemokines, and five growth factors) were measured simultaneously by multiplex bead analysis system. Out of 20 soluble factors, three factors: interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemoattractant protein-1 (MCP-1) were significantly elevated in all groups of vitreoretinal diseases (DME, PDR, BRVO, CRVO, and RRD) compared with control group. According to the correlation analysis in the individual patient''s level, these three factors that were simultaneously increased, did not show any independent upregulation in all the examined diseases. Vascular endothelial growth factor (VEGF) was significantly elevated in patients with PDR and CRVO. In PDR patients, the elevation of VEGF was significantly correlated with the three factors: IL-6, IL-8, and MCP-1, while no significant correlation was observed in CRVO patients. In conclusion, multiplex bead system enabled a comprehensive soluble factor analysis in vitreous fluid derived from variety of patients. Major three factors: IL-6, IL-8, and MCP-1 were strongly correlated with each other indicating a common pathway involved in inflammation process in vitreoretinal diseases.     

The impact of taurine- and beta-alanine-supplemented diets on behavioral and neurochemical parameters in mice: antidepressant versus anxiolytic-like effects

Taurine, a substrate of taurine transporter, has functions as a neuromodulator and antioxidant and beta-alanine, a taurine transporter inhibitor, has a role as a neurotransmitter in the brain, and they were expected to be involved in depression-like behavior and antidepressant treatment. These facts aroused our interest in new capabilities of taurine and beta-alanine. Thus, to investigate the effects of chronic ingestion of taurine- (22.5 mmol/kg diet) supplemented diet and beta-alanine- (22.5 mmol/kg diet) supplemented diet under acute stressful conditions, behavioral changes and brain metabolites were compared with mice fed a control diet. In the open field test, no significant difference was observed in locomotor activity among groups. In the elevated plus-maze test, however, significant increases in the percentage of time spent and entries in the open arms were observed in the beta-alanine-supplemented diet fed group compared to both controls and animals fed with taurine-supplemented diet. Moreover, a significant decrease in the duration of immobility was observed in the taurine-supplemented diet group in the forced swimming test compared to both controls and animals fed with beta-alanine-supplemented diet. Taurine-supplemented diet increased taurine and l-arginine concentrations in the hypothalamus. In contrast, beta-alanine-supplemented diet decreased the concentration of 5-hydroxyindoleacetic acid, a major metabolite of serotonin, in the hypothalamus. Beta-alanine-supplemented diet also increased carnosine (beta-alanyl-l-histidine) concentration in the cerebral cortex and hypothalamus, and brain-derived neurotrophic factor concentration in the hippocampus. These results suggested that taurine-supplemented diet had an antidepressant-like effect and beta-alanine-supplemented diet had an anxiolytic-like effect.     

C-type lectins do not act as functional receptors for filovirus entry into cells

Cellular C-type lectins have been reported to facilitate filovirus infection by binding to glycans on filovirus glycoprotein (GP). However, it is not clearly known whether interaction between C-type lectins and GP mediates all the steps of virus entry (i.e., attachment, internalization, and membrane fusion). In this study, we generated vesicular stomatitis viruses pseudotyped with mutant GPs that have impaired structures of the putative receptor binding regions and thus reduced ability to infect the monkey kidney cells that are routinely used for virus propagation. We found that infectivities of viruses with the mutant GPs dropped in C-type lectin-expressing cells, parallel with those in the monkey kidney cells, whereas binding activities of these GPs to the C-type lectins were not correlated with the reduced infectivities. These results suggest that C-type lectin-mediated entry of filoviruses requires other cellular molecule(s) that may be involved in virion internalization or membrane fusion.     

Mucin 21/Epiglycanin Modulates Cell Adhesion

The molecular structure of mouse Mucin 21 (Muc21)/epiglycanin is proposed to have 98 tandem repeats of 15 amino acids and three exceptional repeats with 12 or 13 amino acids each, followed by a stem domain, a transmembrane domain, and a cytoplasmic tail. A cDNA of Muc21 having 84 tandem repeats of 15 amino acids was constructed and transfected using a Venus vector into HEK 293T cells. The fluorescent cells, which were considered to express Muc21, were nonadherent. This antiadhesion effect was lessened when constructs with smaller numbers of tandem repeats were used, suggesting that the tandem repeat domain plays a crucial role. Cells expressing Muc21 were significantly less adherent to each other and to extracellular matrix components than control cells. Antibody binding to the cell surface integrin subunits α5, α6, and β1 was reduced in Muc21 transfectants in a tandem repeat-dependent manner, whereas equal amounts of proteins were detected by Western blot analysis. Muc21 was expressed as a large glycoprotein that was highly glycosylated with O-glycans at the cell surface, as detected by flow cytometry, Western blotting, and lectin blotting. Although at least a portion of Muc21 was glycosylated with sialylated glycans, removal of sialic acid did not influence the prevention of adhesion.     

Distribution and Function of Macrophage Galactose-type C-type Lectin 2 (MGL2/CD301b): EFFICIENT UPTAKE AND PRESENTATION OF GLYCOSYLATED ANTIGENS BY DENDRITIC CELLS*

Dendritic cells (DCs) express cell surface lectins that are potentially involved in the recognition, uptake, and presentation of glycosylated foreign substances. A unique calcium-type (C-type) lectin, the macrophage galactose (Gal)-type C-type lectin (MGL/CD301) expressed on DCs, is thought to participate in the recognition of molecules from both altered self and pathogens due to its monosaccharide specificity for Gal and N-acetylgalactosamine (GalNAc). Although mice have two MGL genes, Mgl1 and Mgl2, their distinct roles have not been previously explored. The present report characterizes the properties of MGL2 by examining its distribution and its role in antigen presentation by DCs. We generated an MGL2-specific monoclonal antibody and examined MGL2 expression in tissues by immunohistochemistry and in isolated cells by flow cytometry. The cells reactive with this antibody were shown to be a portion of MGL1-expressing cells, mostly conventional DCs. Internalization of soluble polyacrylamide polymers (PAA) with α-GalNAc residues (GalNAc-PAA) by bone marrow-derived DCs (BM-DCs) was mediated by MGL2, as revealed by a comparison of Mgl1^−/− and Mgl2^−/− BM-DCs with wild-type BM-DCs. Biotinylated GalNAc-PAA conjugated to streptavidin (SAv) was more efficiently presented to SAv-primed T cells by BM-DCs than β-N-acetylglucosamine-PAA conjugated to SAv or SAv alone as shown by thymidine uptake and cytokine production. This is the first report that demonstrates the involvement of GalNAc residues in antigen uptake and presentation by DCs that lead to CD4⁺ T cell activation.     

A novel J8 domain gene,IbJ8, inIpomoea batatas (L). Lam.

Sweet potato cDNAs that encode IbJ8, the smallest known J-domain protein, were isolated and characterized. This genome has at least two copies ofIbJ8, which is expressed preferentially in the leaves, flowers, petioles, and stems. Spatial and temporal patterns were studied at different developmental stages, and expression was greater in younger leaves than in older ones. Moreover, expression in roots that arose from single-leaf cuttings was lower at 15, 20, and 30 d than at 40 d, and then the signal was undetectable at 60 d after planting. These results suggest thatIbJ8 expression may be related to the organ age or developmental stage.     

Endothelial lipase modulates susceptibility to atherosclerosis in apolipoprotein-E-deficient mice

Endothelial lipase (EL) expression correlates inversely with circulating high density lipoprotein (HDL) cholesterol levels in genetic mouse models, and human genetic variation in this locus has been linked to differences in HDL cholesterol levels. These data suggest a role for EL in the development of atherosclerotic vascular disease. To investigate this possibility, LIPG-null alleles were bred onto the apoE knockout background, and the homozygous double knockout animals were characterized. Both apoE knockout and double knockout mice had low HDL cholesterol levels when compared with wild-type mice, but the HDL cholesterol levels of the double knockout mice were higher than those of apoE knockout mice. Atherogenic very low density lipoprotein and intermediate density lipoprotein/low density lipoprotein cholesterol levels of the double knockout mice were also greater than those of the apoE knockout animals. Despite this lipid profile, there was a significant approximately 70% decrease in atherosclerotic disease area in double knockout mice on a regular diet. Immunohistochemistry and protein blot studies revealed increased EL expression in the atherosclerotic aortas of the apoE knockout animals. An observed decrease in macrophage content in vessels lacking EL correlated with ex vivo vascular monocyte adhesion assays, suggesting that this protein can modulate monocyte adhesion and infiltration into diseased tissues. These data suggest that EL may have indirect atherogenic actions in vivo through its effect on circulating HDL cholesterol and direct atherogenic actions through vascular wall processes such as monocyte recruitment and cholesterol uptake.