Abstract B17: In-depth proteomics unveils fatty acid oxidation role in controlling vascular permeability

Endothelial cells (ECs) play a key role in maintaining vascular functionality. Alterations in vessel stability and permeability are hallmarks of tumor angiogenesis and may affect the efficacy of anti-cancer therapy. Modulating EC metabolism has emerged as a promising strategy to target angiogenesis in pathological conditions, but so far, little is known about the role of EC metabolism in the regulation of vessel stability and permeability.

In this work we took advantage of a simplified in-vitro model of angiogenesis, where HUVECs (human umbilical vein endothelial cells) form a vascular-like network on a tridimensional matrix, to elucidate the role of EC metabolism during this process.

By integrating high resolution proteomic data with a human genome scale metabolic model we built up the first predictive model of metabolic fluxes occurring in ECs forming a complex network and identified increased fluxes for reactions involving fatty acid oxidation (FAO) enzymes when ECs are assembled into a fully formed network. Upon inhibition of CPT1, the FAO rate-limiting enzyme, we disrupted the network and reduced cellular ATP levels and oxygen consumption, which were restored by replenishing the tricarboxylic acid cycle (TCAc). Remarkably, phosphoproteomic changes measured upon CPT1A inhibition evoked those triggered by thrombin, a potent inducer of EC permeability through calcium signaling. Indeed, acute CPT1A inhibition increased EC permeability in-vitro and leakage of fully formed blood vessel in-vivo, which were restored by replenishing the TCAc or inhibiting calcium influx.

FAO emerges as central regulator of blood vessel stability, revealing the possibility of targeting FAO to interfere with tumor vessel permeability.

Citation Format: Francesca Patella, Zachary T. Schug, Erez Persi, Lisa J. Neilson, Zahra Erami, Daniele Avanzato, Federica Maione, Juan R. Hernandez-Fernaud, Gillian Mackay, Liang Zheng, Steven Reid, Christian Frezza, Enrico Giraudo, Alessandra Fiorio Pla, Kurt Anderson, Eytan Ruppin, Eyal Gottlieb, Sara Zanivan. In-depth proteomics unveils fatty acid oxidation role in controlling vascular permeability. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Angiogenesis and Vascular Normalization: Bench to Bedside to Biomarkers; Mar 5-8, 2015; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl):Abstract nr B17.

Glutamine synthetase activity fuels nucleotide biosynthesis and supports growth of glutamine-restricted glioblastoma

L-Glutamine (Gln) functions physiologically to balance the carbon and nitrogen requirements of tissues. It has been proposed that in cancer cells undergoing aerobic glycolysis, accelerated anabolism is sustained by Gln-derived carbons, which replenish the tricarboxylic acid (TCA) cycle (anaplerosis). However, it is shown here that in glioblastoma (GBM) cells, almost half of the Gln-derived glutamate (Glu) is secreted and does not enter the TCA cycle, and that inhibiting glutaminolysis does not affect cell proliferation. Moreover, Gln-starved cells are not rescued by TCA cycle replenishment. Instead, the conversion of Glu to Gln by glutamine synthetase (GS; cataplerosis) confers Gln prototrophy, and fuels de novo purine biosynthesis. In both orthotopic GBM models and in patients, (13)C-glucose tracing showed that GS produces Gln from TCA-cycle-derived carbons. Finally, the Gln required for the growth of GBM tumours is contributed only marginally by the circulation, and is mainly either autonomously synthesized by GS-positive glioma cells, or supplied by astrocytes.

Transcriptional and morphological effects of tamoxifen on the early development of zebrafish (Danio rerio)

Tamoxifen is a widely used anticancer drug with both an estrogen agonist and antagonist effect. This study focused on its endocrine disrupting effect, and overall environmental significance. Zebrafish embryos were exposed to different concentrations (0.5, 5, 50 and 500 µg l(-1) ) of tamoxifen for 96 h. The results showed a complex effect of tamoxifen on zebrafish embryo development. For the 500 µg l(-1) exposure group, the heart rate was decreased by 20% and mild defects in caudal fin and skin were observed. Expressions of a series of genes related to endocrine and morphological changes were subsequently tested through quantitative real-time polymerase chain reaction. Bisphenol A as a known estrogen was also tested as an endocrine-related comparison. Among the expression of endocrine-related genes, esr1, ar, cyp19a1b, hsd3b1 and ugt1a1 were all increased by tamoxifen exposure, similar to bisphenol A. The cyp19a1b is a key gene that controls estrogen synthesis. Exposure to 0.5, 5, 50 and 500 µg l(-1) of tamoxifen caused upregulation of cyp19a1b expression to 152%, 568%, 953% and 2024% compared to controls, higher than the effects from the same concentrations of bisphenol A treatment, yet vtg1 was suppressed by 24% from exposure to 500 µg l(-1) tamoxifen. The expression of metabolic-related genes such as cyp1a, cyp1c2, cyp3a65, gpx1a, gstp1, gsr and genes related to observed morphological changes such as krt17 were also found to be upregulated by high concentrations of tamoxifen. These findings indicated the potential environmental effect of tamoxifen on teleost early development. Copyright © 2015 John Wiley & Sons, Ltd.

Protective effect of Esculin in adjuvant-induced arthritic (AIA) rats via attenuating pro-inflammatory cytokines and oxidative stress

The present study was intended to exemplify the protective effect of Esculin (ES; 6,7-dihydroxycoumarin-6-o-glucoside) on the adjuvant induced arthritis in adult female Sprague Dawley rats. It has been found that, treatment of ES has significantly improved the body weight of rats accompanied with a reduction of paw volume in comparison to arthritic control. In addition, ES exhibit inhibitory effect on various pro-inflammatory cytokines, for instance, IL-1β and TNF-α. The level of oxidative stress markers, i.e., nitric oxide and peroxide was also found suppressed after treatment. The treatment of ES prevents the tissue injury mediated via oxidative stress via up-regulating the level of endogenous GSH in a dose dependent manner. Thus, it has been corroborated that, ES exerts potent anti-arthritic activity via attenuating pro-inflammatory cytokines and oxidative stress.

Soybeans or Soybean Products Consumption and Depressive Symptoms in Older Residents in Rural Northeast China: A Cross-Sectional Study

OBJECTIVE

Depression is one of the most common mental disorders among elderly subjects. The purpose of this study is to estimate the prevalence of depressive symptoms and the association between soybeans consumption and depressive symptoms among older residents in rural Northeast China.

DESIGN

Cross-sectional study.

SETTING

A representative sample of the rural Northeast residents.

PARTICIPANTS

This survey was conducted from July 2012 to August 2013 which randomly selected and examined a total of 1717 residents aged ≥ 65 years from the rural Northeast China.

MEASUREMENTS

All participants completed the Patient Health Questionnaire-9 (PHQ-9). Information on demographic and lifestyle characteristics and blood biochemical indexes were collected by well-trained personnel.

RESULTS

The prevalence of depressive symptoms in the elderly was 8.9%. Women had significantly higher prevalence of depressive symptoms than men (13.3% vs.4.6%, P<0.001). Individuals consuming soybeans ≥4times/week had statically lower possibility to have depressive symptoms than those rarely consuming (3.6%vs. 12.5%, P<0.05). In addition to some conventional risk factors like sex, annual income, educational status, current smoking and chronic diseases status were associated with depressive symptoms, proper sleep duration (7-8h/d) [OR(95%CI):0.28(0.15,0.53)] and frequently consumption of soybeans or soybean products [OR (95%CI): 0.36 (0.15,0.87) for 2-3times/week and OR (95%CI):0.50 (0.34,0.74) for ≥4times/week] significantly decreased the risk of depressive symptoms among elderly in rural Northeast China.

CONCLUSION

Women had significantly higher prevalence of depressive symptoms than men in rural China. Individuals who rarely consume soybeans or soybean products are more likely to suffer depressive symptoms. Rural elderly residents should be cautiously screened to prevent or treat depression.

Pyruvate carboxylation enables growth of SDH-deficient cells by supporting aspartate biosynthesis

Succinate dehydrogenase (SDH) is a heterotetrameric nuclear-encoded complex responsible for the oxidation of succinate to fumarate in the tricarboxylic acid cycle. Loss-of-function mutations in any of the SDH genes are associated with cancer formation. However, the impact of SDH loss on cell metabolism and the mechanisms enabling growth of SDH-defective cells are largely unknown. Here, we generated Sdhb-ablated kidney mouse cells and used comparative metabolomics and stable-isotope-labelling approaches to identify nutritional requirements and metabolic adaptations to SDH loss. We found that lack of SDH activity commits cells to consume extracellular pyruvate, which sustains Warburg-like bioenergetic features. We further demonstrated that pyruvate carboxylation diverts glucose-derived carbons into aspartate biosynthesis, thus sustaining cell growth. By identifying pyruvate carboxylase as essential for the proliferation and tumorigenic capacity of SDH-deficient cells, this study revealed a metabolic vulnerability for potential future treatment of SDH-associated malignancies.

Inflammation induced by increased frequency of intermittent hypoxia is attenuated by tempol administration

The levels of serum inflammatory cytokines and the activation of nuclear factor kappa B (NF-κB) and hypoxia inducible factor-1α (HIF-1α) in heart tissues in response to different frequencies of intermittent hypoxia (IH) and the antioxidant tempol were evaluated. Wistar rats (64 males, 200-220 g) were randomly divided into 6 experimental groups and 2 control groups. Four groups were exposed to IH 10, 20, 30, or 40 times/h. The other 2 experimental groups were challenged with IH (30 times/h) plus tempol, either beginning on day 0 (IH30T0) or on day 29 (IH30T29). After 6 weeks of challenge, serum levels of tumor necrosis factor (TNF)-α, intracellular adhesion molecule (ICAM)-1, and interleukin-10 were measured, and western blot analysis was used to detect NF-κB p65 and HIF-1α in myocardial tissues. Serum levels of TNF-α and ICAM-1 and myocardial expression of NF-κB p65 and HIF-1α were all significantly higher in IH rats than in controls (P<0.001). Increased IH frequency resulted in more significant changes. Administration of tempol in IH rats significantly reduced levels of TNF-α, ICAM-1, NF-κB and HIF-1α compared with the non-tempol-treated group (F=16.936, P<0.001). IH induced an inflammatory response in a frequency-dependent manner. Additionally, HIF-1α and NF-κB were increased following IH administration. Importantly, tempol treatment attenuated this effect.

New measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

Support vector machine in crash prediction at the level of traffic analysis zones: Assessing the spatial proximity effects

In zone-level crash prediction, accounting for spatial dependence has become an extensively studied topic. This study proposes Support Vector Machine (SVM) model to address complex, large and multi-dimensional spatial data in crash prediction. Correlation-based Feature Selector (CFS) was applied to evaluate candidate factors possibly related to zonal crash frequency in handling high-dimension spatial data. To demonstrate the proposed approaches and to compare them with the Bayesian spatial model with conditional autoregressive prior (i.e., CAR), a dataset in Hillsborough county of Florida was employed. The results showed that SVM models accounting for spatial proximity outperform the non-spatial model in terms of model fitting and predictive performance, which indicates the reasonableness of considering cross-zonal spatial correlations. The best model predictive capability, relatively, is associated with the model considering proximity of the centroid distance by choosing the RBF kernel and setting the 10% of the whole dataset as the testing data, which further exhibits SVM models' capacity for addressing comparatively complex spatial data in regional crash prediction modeling. Moreover, SVM models exhibit the better goodness-of-fit compared with CAR models when utilizing the whole dataset as the samples. A sensitivity analysis of the centroid-distance-based spatial SVM models was conducted to capture the impacts of explanatory variables on the mean predicted probabilities for crash occurrence. While the results conform to the coefficient estimation in the CAR models, which supports the employment of the SVM model as an alternative in regional safety modeling.

Analysis of Cell Metabolism Using LC-MS and Isotope Tracers

Here we discuss our methods to analyze small polar compounds involved in central carbon metabolism using LC-MS. Methods described include sample extraction procedures for cells and medium, as well as for plasma/serum, urine, CSF, and tissue samples. Different extraction solvents are assessed. Our methods for using (13)C stable isotope tracers to examine the kinetics and distributions of mass isotopologues of many metabolites are discussed. Quantification methods are described for (13)C stable isotope tracer experiments as well as for unlabeled experiments. These methods were applied in a fumarate hydratase deficient cell model to show how isotope tracing can demonstrate shifts in metabolic pathways and, together with metabolite exchange rates, can be used to gain insights into changes in cell metabolism.