Inflammation, DNA-centered radicals, and oxidative genotoxicity: The role of HOCl produced by myeloperoxidase in carcinogenesis

Myeloid cells (macrophages and neutrophils) infiltrate and synthesize myeloperoxidase (MPO) in sites of inflammation, producing gentotoxicity. In RAW 264.7 macrophages, bacterial lipopolysaccharide (LPS) induces superoxide radical anion, nuclear deformation (nuclear protuberances), MPO synthesis, biomolecule oxidation and cell death. “Freezing” LPS-triggered macrophage activation with the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) prevented cell activation and death. Oxidation of proteins and genomic DNA was also blocked, with formation of protein- and DNA-DMPO nitrone adducts, as analyzed by immuno-spin trapping with a polyclonal anti-DMPO serum. Interestingly, confocal microscopy analysis of these cells showed that MPO, genomic DNA, and DNA-DMPO nitrone adducts co-localized in the nuclear protuberances. These observations, and the fact that DNA is negatively charged and MPO is a cationic protein, suggest a role for uptaken or newly synthesized MPO in oxidative genotoxicity induced by myeloid cells in sites of inflammation. 
In order to understand MPO-induced formation of DNA-centered radicals, we studied DNA-DMPO nitrone adducts in calf thymus DNA treated with micromolar concentrations of hypochlorous acid (HOCl) added as a bolus or generated in situ by the MPO/H2O2/Cl- system in the presence of DMPO. We also investigated DNA-DMPO nitrone adducts inside living cells containing MPO. The cell models we used were: i) human leukemia (HL)-60 cells, which overexpress MPO, ii) RAW 264.7 macrophages activated with LPS (1 ng/ml for 24 h), to induce MPO, and iii) A549 human airway epithelial cells pre-loaded with human MPO. When these cells were activated with the phorbol ester PMA, the number of 6-thioguanine-resistant cells with the hypoxanthine-guanine phosphoribosyl transferase (HRPT) mutation increased. This mutation was prevented by each of the following: the NADPH oxidase inhibitor apocynin; the MPO inhibitors salicylhydroxamic acid and 4-aminobenzoic acid hydrazide; the cell-permeable HOCl scavenger resveratrol; and DMPO, which traps DNA-centered radicals and prevents further oxidation. 
Genomic DNA-centered radicals and further mutagenesis induced by activated myeloid cells in sites of inflammation can be prevented by blocking MPO activity, preventing formation of and/or scavenging HOCl, or trapping DNA-centered radicals. Our findings provide new therapeutic avenues for preventing carcinogenesis induced by infiltration and activation of myeloid cells in sites of inflammation, for example, in the lung exposed to particulate matter. SUPPORTED BY NIEHS 5R00ES015415-03
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Le prototypage basé sur des méta données phase 1 du cycle de développement

Le processus de conception des systèmes d'information (SI) est un processus long et complexe qui résulte en de nombreux échecs. Le prototypage informatique et la conception guidée par modèles ont été proposés comme une solution en améliorant la qualité des spécifications au début du cycle de vie d'un SI. L'objectif de notre recherche est de mieux orienter l'action de spécification des exigences dans la phase initiale de conception "Communication Client - Concepteur" et dans le début de la phase de développement "Communication Concepteur - Développeur" en utilisant des artefacts de prototypage. Notre travail ouvre concrètement une voie dans laquelle il devient possible d'envisager que toute modification au cours de la vie d'un SI puisse être effectuée à partir du modèle du domaine qui est l'intrant du "prototypeur", qui devient alors le SI lui-même. Mots clés: système d'information; méthodologie de conception; modèle conceptuel de données; spécification déclarative; spécification exécutable; prototype; méta-donnée; architecture applicativeDesigning information systems is a lengthy and complex process that leads to numerous failures. Prototyping has been proposed as a solution to improve the specifications' quality in the beginning of an information system's life cycle. Every information system (IS) is based upon the information architecture ; it is, before all, a content about the perceived reality. A "domain" is a formalization of the perceived reality in which the IS users identify the representations of facts (the data) by means of semantic keys. IS designers have to transform this model using their knowledge about the abstract functioning of computers. The objective of our research is to guide the action of requirements specification in the initial design phase of "Communication Customer - Designer" and in the beginning of the development phase "Communication Designer - Developer" using prototyping artifacts. Our work actually opens the way where it becomes possible to envisage that every modification during the information system's life cycle could be done from within the domain model, which is an input for the "prototyper" and becomes then itself an information system. Keywords : information system ; design method ; conceptual data model ; déclarative specification; executables pecification; prototype ; méta-data ; application architectur

The Nitrone Spin Trap 5,5-Dimethyl-1-pyrroline N-oxide Affects Stress Response and Fate of Lipopolysaccharide-Primed RAW 264.7 Macrophage Cells

The nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) is commonly used to study free radicals. Due to its free radical trapping properties, DMPO is thought to reduce free radial-mediated oxidative damage and other related cellular responses. The purpose of this study was to assess the effect of DMPO on lipopolysaccharide (LPS)-induced inflammation, endoplasmic reticulum (ER) stress, and apoptosis in RAW 264.7 cells. The results showed that DMPO at 50 mM inhibited inducible nitric oxide synthase expression when added shortly after LPS treatment (≤3 h). Interestingly, DMPO increased anti-inflammatory heme oxygenase-1 (HO-1) expression and reversed LPS-induced decrease in HO-1 expression. LPS could increase cellular ER stress as indicated by C/EBP homologous protein (CHOP) induction; DMPO reduced LPS effect on CHOP expression. Unexpectedly, DMPO had a synergistic effect with LPS on increased caspase-3 activity. Overall, DMPO harbors multiple modulating effects but may induce apoptosis in LPS-stressed cells when given at 50 mM, an effective dose for its anti-inflammatory activity in vitro. Our data provide clues for further understanding of the nitrone spin trap with therapeutic potential.Fil: Zhai, Zili. University of Chicago. Department of Medicine. Section of Gastroenterology; Estados UnidosFil: Ramirez, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; ArgentinaFil: Gomez-Mejiba, Sandra Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentin

Comparativa entre la predicción de una inteligencia artificial y el cálculo de la fórmula matemática en el tiempo de operación de un relé con protección de sobrecorriente 51 con curva ANSI very inverse

Este trabajo se enfoca en realizar una comparación entre la predicción de una inteligencia artificial y una fórmula matemática que calcula el tiempo de operación de un relé de protección de sobre corriente con curva ANSI very inverse. Para hacer esta comparación primero se construyó una red neuronal que aprenda a predecir el tiempo de operación de un relé de protección de sobre corriente con curva ANSI very inverse; luego se desarrolla una interfaz web donde se puede visualizar los resultados de la predicción de la red neuronal y los resultados del cálculo matemático con la formula mencionada anteriormente. Para construir la red neuronal se utilizó la interfaz Google Colab con lenguaje de programación Python; y para construir la Interfaz web se utilizó HTML, CSS y Javascript. Con la red neuronal y la interfaz web desarrollados, se realiza la comparación entre la predicción de la red neuronal y una fórmula matemática que calcula el tiempo de operación de un relé de protección de sobre corriente con curva ANSI very inverse; con 3 ejemplos, donde se realiza discusiones, observaciones y conclusiones