Natural Killer Cell Inhibitory Receptors Block Actin Cytoskeleton-dependent Recruitment of 2B4 (CD244) to Lipid Rafts

A dynamic balance of positive and negative signals regulates target cell lysis by natural killer (NK) cells upon engagement of a variety of different activation receptors and of inhibitory receptors that recruit the tyrosine phosphatase SHP-1. However, the step at which activation signals are blocked by SHP-1 is not known. We have been using activation receptor 2B4 (CD244) to study the influence of inhibitory receptors on NK cell activation. Engagement of inhibitory receptors by HLA class I on target cells blocks phosphorylation of 2B4, placing the inhibitory step at the level, or upstream of 2B4 phosphorylation. Here we show that phosphorylated 2B4, after engagement with either antibodies or target cells that express the 2B4 ligand, is found exclusively in a detergent-resistant membrane fraction that contains lipid rafts. Integrity of lipid rafts was essential for phosphorylation and activating function of 2B4. Coengagement of inhibitory receptors blocked 2B4 phosphorylation and 2B4 association with detergent-resistant membranes, indicating that inhibitory receptors function upstream of raft-dependent signals. Recruitment of 2B4 into detergent-resistant membrane fractions and 2B4 phosphorylation were dependent on actin polymerization. Blocking actin cytoskeleton-dependent raft recruitment of different receptors may be a general mechanism by which inhibitory receptors control NK cell activation

Расчет гашения обратного напряжения в импульсной схеме

Grid and e-science infrastructure interoperability is an increasing demand for Grid applications but interoperability based on common open standards adopted by Grid middle-wares are only starting to emerge on Grid infrastructures and are not broadly provided today. In earlier work we have shown how open standards can be improved by lessons learned from cross-Grid applications that require access to both, High Throughput Computing (HTC) resources as well as High Performance Computing (HPC) resources. This paper provides more insights in several concepts with a particular focus on effectively describing Grid job descriptions in order to satisfy the demands of e-scientists and their cross-Grid applications. Based on lessons learned over years gained with interoperability setups between production Grids such as EGEE, DEISA, and NorduGrid, we illustrate how common open Grid standards (i.e. JSDL and GLUE2) can take cross-Grid application experience into account

Prediction of fruit and vegetable intake from biomarkers using individual participant data of diet-controlled intervention studies

Fruit and vegetable consumption produces changes in several biomarkers in blood. The present study aimed to examine the dose–response curve between fruit and vegetable consumption and carotenoid (α-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein and zeaxanthin), folate and vitamin C concentrations. Furthermore, a prediction model of fruit and vegetable intake based on these biomarkers and subject characteristics (i.e. age, sex, BMI and smoking status) was established. Data from twelve diet-controlled intervention studies were obtained to develop a prediction model for fruit and vegetable intake (including and excluding fruit and vegetable juices). The study population in the present individual participant data meta-analysis consisted of 526 men and women. Carotenoid, folate and vitamin C concentrations showed a positive relationship with fruit and vegetable intake. Measures of performance for the prediction model were calculated using cross-validation. For the prediction model of fruit, vegetable and juice intake, the root mean squared error (RMSE) was 258·0 g, the correlation between observed and predicted intake was 0·78 and the mean difference between observed and predicted intake was − 1·7 g (limits of agreement: − 466·3, 462·8 g). For the prediction of fruit and vegetable intake (excluding juices), the RMSE was 201·1 g, the correlation was 0·65 and the mean bias was 2·4 g (limits of agreement: − 368·2, 373·0 g). The prediction models which include the biomarkers and subject characteristics may be used to estimate average intake at the group level and to investigate the ranking of individuals with regard to their intake of fruit and vegetables when validating questionnaires that measure intake.</jats:p

Expression Analysis of the Ligands for the Natural Killer Cell Receptors NKp30 and NKp44

BACKGROUND: The natural cytotoxicity receptors (NCR) are important to stimulate the activity of Natural Killer (NK) cells against transformed cells. Identification of NCR ligands and their level of expression on normal and neoplastic cells has important implications for the rational design of immunotherapy strategies for cancer. METHODOLOGY/PRINCIPAL FINDINGS: Here we analyze the expression of NKp30 ligand and NKp44 ligand on 30 transformed or non-transformed cell lines of different origin. We find intracellular and surface expression of these two ligands on almost all cell lines tested. Expression of NKp30 and NKp44 ligands was variable and did not correlate with the origin of the cell line. Expression of NKp30 and NKp44 ligand correlated with NKp30 and NKp44-mediated NK cell lysis of tumor cells, respectively. The surface expression of NKp30 ligand and NKp44 ligand was sensitive to trypsin treatment and was reduced in cells arrested in G(2)/M phase. CONCLUSION/SIGNIFICANCE: These data demonstrate the ubiquitous expression of the ligands for NKp30 and NKp44 and give an important insight into the regulation of these ligands

Modulation of NKp30- and NKp46-Mediated Natural Killer Cell Responses by Poxviral Hemagglutinin

Natural killer (NK) cells are an important element in the immune defense against the orthopox family members vaccinia virus (VV) and ectromelia virus (ECTV). NK cells are regulated through inhibitory and activating signaling receptors, the latter involving NKG2D and the natural cytotoxicity receptors (NCR), NKp46, NKp44 and NKp30. Here we report that VV infection results in an upregulation of ligand structures for NKp30 and NKp46 on infected cells, whereas the binding of NKp44 and NKG2D was not significantly affected. Likewise, infection with ectromelia virus (ECTV), the mousepox agent, enhanced binding of NKp30 and, to a lesser extent, NKp46. The hemagglutinin (HA) molecules from VV and ECTV, which are known virulence factors, were identified as novel ligands for NKp30 and NKp46. Using NK cells with selectively silenced NCR expression and NCR-CD3ζ reporter cells, we observed that HA present on the surface of VV-infected cells, or in the form of recombinant soluble protein, was able to block NKp30-triggered activation, whereas it stimulated the activation through NKp46. The net effect of this complex influence on NK cell activity resulted in a decreased NK lysis susceptibility of infected cells at late time points of VV infection when HA was expression was pronounced. We conclude that poxviral HA represents a conserved ligand of NCR, exerting a novel immune escape mechanism through its blocking effect on NKp30-mediated activation at a late stage of infection

Evaluation and Characterization of Bacterial Metabolic Dynamics with a Novel Profiling Technique, Real-Time Metabolotyping

BACKGROUND: Environmental processes in ecosystems are dynamically altered by several metabolic responses in microorganisms, including intracellular sensing and pumping, battle for survival, and supply of or competition for nutrients. Notably, intestinal bacteria maintain homeostatic balance in mammals via multiple dynamic biochemical reactions to produce several metabolites from undigested food, and those metabolites exert various effects on mammalian cells in a time-dependent manner. We have established a method for the analysis of bacterial metabolic dynamics in real time and used it in combination with statistical NMR procedures. METHODOLOGY/PRINCIPAL FINDINGS: We developed a novel method called real-time metabolotyping (RT-MT), which performs sequential (1)H-NMR profiling and two-dimensional (2D) (1)H, (13)C-HSQC (heteronuclear single quantum coherence) profiling during bacterial growth in an NMR tube. The profiles were evaluated with such statistical methods as Z-score analysis, principal components analysis, and time series of statistical TOtal Correlation SpectroScopY (TOCSY). In addition, using 2D (1)H, (13)C-HSQC with the stable isotope labeling technique, we observed the metabolic kinetics of specific biochemical reactions based on time-dependent 2D kinetic profiles. Using these methods, we clarified the pathway for linolenic acid hydrogenation by a gastrointestinal bacterium, Butyrivibrio fibrisolvens. We identified trans11, cis13 conjugated linoleic acid as the intermediate of linolenic acid hydrogenation by B. fibrisolvens, based on the results of (13)C-labeling RT-MT experiments. In addition, we showed that the biohydrogenation of polyunsaturated fatty acids serves as a defense mechanism against their toxic effects. CONCLUSIONS: RT-MT is useful for the characterization of beneficial bacterium that shows potential for use as probiotic by producing bioactive compounds

Prevalence and incidence of iron deficiency in European community-dwelling older adults : An observational analysis of the DO-HEALTH trial

Background and aim Iron deficiency is associated with increased morbidity and mortality in older adults. However, data on its prevalence and incidence among older adults is limited. The aim of this study was to investigate the prevalence and incidence of iron deficiency in European community-dwelling older adults aged ≥ 70 years. Methods Secondary analysis of the DO-HEALTH trial, a 3-year clinical trial including 2157 community-dwelling adults aged ≥ 70 years from Austria, France, Germany, Portugal and Switzerland. Iron deficiency was defined as soluble transferrin receptor (sTfR) > 28.1 nmol/L. Prevalence and incidence rate (IR) of iron deficiency per 100 person-years were examined overall and stratified by sex, age group, and country. Sensitivity analysis for three commonly used definitions of iron deficiency (ferritin  1.5) were also performed. Results Out of 2157 participants, 2141 had sTfR measured at baseline (mean age 74.9 years; 61.5% women). The prevalence of iron deficiency at baseline was 26.8%, and did not differ by sex, but by age (35.6% in age group ≥ 80, 29.3% in age group 75–79, 23.2% in age group 70–74); P  1.5. Occurrences of iron deficiency were observed with IR per 100 person-years of 9.2 (95% CI 8.3–10.1) and did not significantly differ by sex or age group. The highest IR per 100 person-years was observed in Austria (20.8, 95% CI 16.1–26.9), the lowest in Germany (6.1, 95% CI 4.7–8.0). Regarding the other definitions of iron deficiency, the IR per 100 person-years was 4.5 (95% CI 4.0–4.9) for ferritin  1.5. Conclusions Iron deficiency is frequent among relatively healthy European older adults, with people aged ≥ 80 years and residence in Austria and Portugal associated with the highest risk

What Is New for an Old Molecule? Systematic Review and Recommendations on the Use of Resveratrol

Stilbenes are naturally occurring phytoalexins that generally exist as their more stable E isomers. The most well known natural stilbene is resveratrol (Res), firstly isolated in 1939 from roots of Veratrum grandiflorum (white hellebore) (1) and since then found in various edible plants, notably in Vitis vinifera L. (Vitaceae) (2). The therapeutic potential of Res covers a wide range of diseases, and multiple beneficial effects on human health such as antioxidant, anti-inflammatory and anti-cancer activities have been suggested based on several in vitro and animal studies (3). In particular, Res has been reported to be an inhibitor of carcinogenesis at multiple stages via its ability to inhibit cyclooxygenase, and is an anticancer agent with a role in antiangiogenesis (4). Moreover, both in vitro and in vivo studies showed that Res induces cell cycle arrest and apoptosis in tumor cells (4). However, clinical studies in humans evidenced that Res is rapidly absorbed after oral intake, and that the low level observed in the blood stream is caused by a fast conversion into metabolites that are readily excreted from the body (5). Thus, considerable efforts have gone in the design and synthesis of Res analogues with enhanced metabolic stability. Considering that reduced Res (dihydro- resveratrol, D-Res) conjugates may account for as much as 50% of an oral Res dose (5), and that D-Res has a strong proliferative effect on hormone-sensitive cancer cell lines such as breast cancer cell line MCF7 (6), we recently devoted our synthetic efforts to the preparation of trans-restricted analogues of Res in which the E carbon-carbon double bond is embedded into an imidazole nucleus. To keep the trans geometry, the two aryl rings were linked to the heteroaromatic core in a 1,3 fashion. Based on this design, we successfully prepared a variety of 1,4-, 2,4- and 2,5-diaryl substituted imidazoles including Res analogues 1, 2 and 3, respectively, by procedures that involve transition metal-catalyzed Suzuki-Miyaura cross-coupling reactions and highly selective N-H or C-H direct arylation reactions as key synthetic steps. The anticancer activity of compounds 1–3 was evaluated against the 60 human cancer cell lines panel of the National Cancer Institute (NCI, USA). The obtained results, that will be showed and discussed along with the protocols developed for the preparation of imidazoles 1–3, confirmed that a structural optimization of Res may provide analogues with improved potency in inhibiting the growth of human cancer cell lines in vitro when compared to their natural lead. (1) Takaoka,M.J.Chem.Soc.Jpn.1939,60,1090-1100. (2) Langcake, P.; Pryce, R. J. Physiological. Plant Patology 1976, 9, 77-86. (3) Vang, O.; et al. PLoS ONE 2011, 6, e19881. doi:10.1371/journal.pone.0019881 (4) Kraft, T. E.; et al. Critical Reviews in Food Science and Nutrition 2009, 49, 782-799. (5) Walle, T. Ann. N.Y. Acad. Sci. 2011, 1215, 9-15. doi: 10.1111/j.1749-6632.2010.05842.x (6) Gakh,A.A.;etal.Bioorg.Med.Chem.Lett.2010,20,6149-6151