A Role for Cadherin-5 in Regulation of Vascular Endothelial Growth Factor Receptor 2 Activity in Endothelial Cells

FLK-1/vascular endothelial growth factor receptor 2 (VEGFR-2) is one of the receptors for VEGF. In this study we examined the effect of cell density on activation of VEGFR-2. VEGF induces only very slight tyrosine phosphorylation of VEGFR-2 in confluent (95-100% confluent) pig aortic endothelial (PAE) cells. In contrast, robust VEGF-dependent tyrosine phosphorylation of VEGFR-2 was observed in cells plated in sparse culture conditions (60-65% confluent). A similar cell density-dependent phenomenon was observed in different endothelial cells but not in NIH-3T3 fibroblast cells expressing VEGFR-2. Stimulating cells with high concentrations of VEGF or replacing the extracellular domain of VEGFR-2 with that of the colony-stimulating factor 1 receptor did not alleviate the sensitivity of VEGFR-2 to cell density, indicating that the confluent cells were probably not secreting an antagonist to VEGF. Furthermore, in PAE cells, ectopically introduced platelet-derived growth factor alpha receptor could be activated at both high and low cell density conditions, indicating that the density effect was not universal for all receptor tyrosine kinases expressed in endothelial cells. In addition to lowering the density of cells, removing divalent cations from the medium of confluent cells potentiated VEGFR-2 phosphorylation in response to VEGF. These findings suggested that cell-cell contact may be playing a role in regulating the activation of VEGFR-2. To this end, pretreatment of confluent PAE cells with a neutralizing anti-cadherin-5 antibody potentiated the response of VEGFR-2 to VEGF. Our data demonstrate that endothelial cell density plays a critical role in regulating VEGFR-2 activity, and that the underlying mechanism appears to involve cadherin-5.     

Toward nanoscale genome sequencing

This article reports on the state-of-the-art technologies that sequence DNA using miniaturized devices. The article considers the miniaturization of existing technologies for sequencing DNA and the opportunities for cost reduction that 'on-chip' devices can deliver. The ability to construct nano-scale structures and perform measurements using novel nano-scale effects has provided new opportunities to identify nucleotides directly using physical, and not chemical, methods. The challenges that these technologies need to overcome to provide a US$1000-genome sequencing technology are also presented.     

Relationship between serum high sensitivity C-reactive protein with angiographic severity of coronary artery disease and traditional cardiovascular risk factors

Serum high-sensitivity C-reactive protein (hs-CRP) is predictive of coronary artery disease (CAD). The aim of this study was to examine the possible association of hs-CRP with presence and severity of CAD and traditional CAD risk factors. This case-control study was carried out on 2,346 individuals from September 2011 to May 2013. Of these 1,187 had evidence of coronary disease, and were subject to coronary angiography, and the remainder were healthy controls (n = 1,159). Characteristics were determined using standard laboratory techniques and serum Hs-CRP levels were estimated using enzyme-linked immunosorbent assay (ELISA) kits, and severity of CAD was assessed according to the score of obstruction in coronary artery. Serum hs-CRP levels were higher in those with severe coronary disease, who had stenosis ≥ 50% stenosis of at least one coronary artery (all p < 0.001 vs. individuals in healthy control), and correlated significantly with the score for coronary artery disease (all p < 0.01). After adjustment for conventional risk factors, regression analysis revealed that smoking habits, fasting blood glucose, total cholesterol, high-density lipoprotein, hs-CRP, blood pressure, anxiety, dietary intake of vitamin E, and cholesterol remained as independent determinants for angiographic severity of CAD. The area under the receiving operating characteristic (ROC) curve for serum hs-CRP was 0.869 (CI 95% 0.721–0.872, p < 0.001). The optimal values for the cut-off point was a serum hs-CRP of 2.78 mg/l (sensitivity 80.20%, specificity 85%) to predict severity of CAD. Increased serum hs-CRP levels are significantly associated with angiographic severity of CAD, suggesting its value as a biomarkers for predicting CAD.     

Effect of Ohmic Heating on the Formation and Texture of Acid Milk Gels

Food Biophysics - This study aimed to describe the effects of ohmic heat treatment (OHT) of milk on the formation and properties of acid milk gels. The influence of voltage gradient (25, 40,...     

Effect of salicylic acid and yeast extract on the accumulation of jasmonic acid and sesquiterpenoids in Panax ginseng adventitious roots

In different plant species, secondary metabolite biosynthesis is regulated by the phytohormone jasmonic acid (JA), which is derived by the action of lipoxygenase. In this study, we examined mono- and sesquiterpenoid accumulation and the related signal transduction pathways and biosynthetic genes in adventitious root cultures of Panax ginseng C.A. Meyer as induced by yeast extract (YE, 3 g/L), a biotic elicitor, and salicylic acid (SA, 200 μM), a signaling elicitor. The lipoxygenase (LOX) gene was highly expressed in 24 and 12 h after treatment with SA and YE. JA content was significantly increased in 24 h after SA treatment. The H₂O₂ content was the highest in 24 and 72 h after the onset of SA and YE treatment, respectively. RNA blot analysis showed that farnesyl diphosphate synthase (FPS) and isopentenyl pyrophosphate isomerase (IPPI) genes encoding enzymes of the biosynthesis of mono- and sesquiterpenoids were up-regulated by both elicitors. Farensol, isochiapin B sesquiterpenoids, champhor, and cineole monoterpenoids were highly accumulated after 24 h of SA treatment, while YE treatment induced bacchotricuneatin C, guaiazulene, isochiapin B, and p-benzoquinone sesquiterpenoid production. These results suggest that mono- and sesquiterpenoid accumulation induced by SA and YE occurs due to the IPPI and FPS expression and may be mediated by reactive oxygen species signaling and jasmonic acid signal transduction.     

Electrosensitive polyacrylic acid/fibrin hydrogel facilitates cell seeding and alignment

Three-dimensional cell culture and conditioning is an effective means to guide cell distribution and patterning for tissue engineered constructs such as vascular grafts. Polyacrylic acid is known as an electroresponsive polymer, capable of transforming environmental stimuli like electrical energy to mechanical forces. In this study, we developed an electrosensitive and biocompatible hydrogel-based smart device composed of acrylic acid and fibrin as a tissue engineered construct to mechanically stimulate cells. Structural properties of the hydrogel were assessed by FTIR-ATR, scanning electron microscopy, prosimetry, and swelling measurement. Distribution and alignment of porcine smooth muscle cells (pSMCs) seeded on the surface of lyophilized hydrogels were evaluated and quantified by two-photon laser scanning microscopy. Smooth muscle cell tissue constructs exposed to 2 h of pulsatile electrical stimulation showed significantly enhanced cell penetration and alignment due to dynamic changes produced by alternative swelling and deswelling, in comparison with static samples. On the basis of the results, this hydrogel under electrical stimulation works as a mechanical pump, which can direct SMC alignment and facilitate infiltration and distribution of cells throughout the structure.     

The Genomic Landscape of TP53 and p53 Annotated High Grade Ovarian Serous Carcinomas from a Defined Founder Population Associated with Patient Outcome

High-grade ovarian serous carcinomas (HGSC) are characterized by TP53 mutations and non-random patterns of chromosomal anomalies, where the nature of the TP53 mutation may correlate with clinical outcome. However, the frequency of common somatic genomic events occurring in HGSCs from demographically defined populations has not been explored. Whole genome SNP array, and TP53 mutation, gene and protein expression analyses were assessed in 87 confirmed HGSC samples with clinical correlates from French Canadians, a population exhibiting strong founder effects, and results were compared with independent reports describing similar analyses from unselected populations. TP53 mutations were identified in 91% of HGSCs. Anomalies observed in more than 50% of TP53 mutation-positive HGSCs involved gains of 3q, 8q and 20q, and losses of 4q, 5q, 6q, 8p, 13q, 16q, 17p, 17q, 22q and Xp. Nearly 400 regions of non-overlapping amplification or deletion were identified, where 178 amplifications and 98 deletions involved known genes. The subgroup expressing mutant p53 protein exhibited significantly prolonged overall and disease-free survival as compared with the p53 protein null subgroup. Interestingly, a comparative analysis of genomic landscapes revealed a significant enrichment of gains involving 1q, 8q, and 12p intervals in the subgroup expressing mutant p53 protein as compared with the p53 protein null subgroup. Although the findings show that the frequency of TP53 mutations and the genomic landscapes observed in French Canadian samples were similar to those reported for samples from unselected populations, there were differences in the magnitude of global gains/losses of specific chromosomal arms and in the spectrum of amplifications and deletions involving focal regions in individual samples. The findings from our comparative genomic analyses also support the notion that there may be biological differences between HGSCs that could be related to the nature of the TP53 mutation.     

Thymidylate synthase and methionine synthase polymorphisms are not associated with susceptibility to childhood acute lymphoblastic leukemia in Kurdish population from Western Iran

In order to determine the influence of polymorphism in thymidylate synthase (TS 28-bp repeat) and methionine synthase (MS A2756G) genes on the susceptibility to acute lymphoblastic leukemia (ALL), 73 children with ALL and 128 age and sex matched unrelated healthy individuals from the Kermanshah Province of Iran were screened. The genotyping of TS 28-bp repeat and MS A2756G polymorphisms were performed by polymerase chain reaction (PCR) and PCR–RFLP, respectively. The frequency of TS 2R allele in patients and controls were 41.5 and 38%, respectively (Odds ratios (OR) = 1.13, 95%CI 0.73–1.74, P = 0.56). The allelic frequency of G allele of MS was higher (25%) in patients compared with healthy subjects (23%) (OR = 1.09, 95%CI 0.67–1.75, P = 0.71). Considering MS AA and TS 3R3R genotypes as reference indicated that individuals with MS GG + TS 2R2R genotypes have 1.3-fold increase in the risk of ALL (OR = 1.3, 95%CI 0.6–2.7, P = 0.5). Our results showed that neither TS 28-bp repeat nor MS A2756G polymorphisms are risk factors for susceptibility to ALL in Western Iran.     

The sperm surface localization of the TRP-3/SPE-41 Ca2+ -permeable channel depends on SPE-38 function in Caenorhabditis elegans

Despite undergoing normal development and acquiring normal morphology and motility, mutations in spe-38 or trp-3/spe-41 cause identical phenotypes in Caenorhabditis elegans-mutant sperm fail to fertilize oocytes despite direct contact. SPE-38 is a novel, four-pass transmembrane protein and TRP-3/SPE-41 is a Ca(2+)-permeable channel. Localization of both of these proteins is confined to the membranous organelles (MOs) in undifferentiated spermatids. In mature spermatozoa, SPE-38 is localized to the pseudopod and TRP-3/SPE-41 is localized to the whole plasma membrane. Here we show that the dynamic redistribution of TRP-3/SPE-41 from MOs to the plasma membrane is dependent on SPE-38. In spe-38 mutant spermatozoa, TRP-3/SPE-41 is trapped within the MOs and fails to reach the cell surface despite MO fusion with the plasma membrane. Split-ubiquitin yeast-two-hybrid analyses revealed that the cell surface localization of TRP-3/SPE-41 is likely regulated by SPE-38 through a direct protein-protein interaction mechanism. We have identified sequences that influence the physical interaction between SPE-38 and TRP-3/SPE-41, and show that these sequences in SPE-38 are required for fertility in transgenic animals. Despite the mislocalization of TRP-3/SPE-41 in spe-38 mutant spermatozoa, ionomycin or thapsigargin induced influx of Ca(2+) remains unperturbed. This work reveals a new paradigm for the regulated surface localization of a Ca(2+)-permeable channel.