Le rôle du stress oxydant dans les changements épigénétiques contribuant aux complications du syndrome métabolique

La méthylation de l'ADN est l'une des modifications épigénétiques au niveau des îlots CpG. Cette modification épigénétique catalysée par les ADN méthyltransférases (DNMTs) consiste en la méthylation du carbone 5' d’une cytosine ce qui aboutit à la formation de 5-méthylcytosine. La méthylation de l'ADN est clairement impliquée dans l'inactivation des gènes et dans l'empreinte génétique. Elle est modulée par la nutrition, en particulier par les donneurs de méthyle et par une restriction protéique. Ces modifications épigénétiques persistent plus tard dans la vie et conduisent au développement de nombreuses pathologies telles que le syndrome métabolique et le diabète de type 2. En fait, de nombreux gènes clés subissent une modification de leur état de méthylation en présence des composants du syndrome métabolique. Cela montre que la méthylation de l'ADN est un processus important dans l'étiologie du syndrome métabolique. Le premier travail de ce doctorat a porté sur la rédaction d’un article de revue qui a examiné le cadre central du syndrome métabolique et analyser le rôle des modifications épigénétiques susceptibles d'influer sur l'apparition du stress oxydant et des complications cardiométaboliques. D’autre part, les cellules intestinales Caco-2/15, qui ont la capacité de se différencier et d’acquérir les caractéristiques physiologiques de l'intestin grêle, ont été utilisées et traitées avec du Fer-Ascorbate pour induire un stress oxydant. Le Fer-Ascorbate a induit une augmentation significative de l’inflammation et de la peroxydation des lipides (malondialdehyde) ainsi que des altérations de de la défense antioxydante (SOD2 et GPx) accompagnées de modifications épigénétiques. De plus, la pré-incubation des cellules avec de la 5-aza-2'-désoxycytidine, un agent de déméthylation et/ou l’antioxydant Trolox a normalisé la défense antioxydante, réduit la peroxydation des lipides et prévenu l'inflammation. Ce premier travail a démontré que les modifications du redox et l’inflammation induites par le Fer-Ascorbate peuvent impliquer des changements épigénétiques, plus particulièrement des changements dans la méthylation de l’ADN. Pour mieux définir l’impact du stress oxydant au niveau nutritionnel, des cochons d’Inde âgés de trois jours ont été séparés en trois groupes : 1) Témoins: alimentation régulière; 2) Nutrition parentérale (NP) 3) H2O2 : Témoins + 350 uM H2O2. Après quatre jours, pour un groupe, les perfusions ont été stoppées et les animaux sacrifiés pour la collecte des foies. Pour l’autre groupe d’animaux, les perfusions ont été arrêtées et les animaux ont eu un accès libre à une alimentation régulière jusqu'à la fin de l’étude, huit semaines plus tard où ils ont été sacrifiés pour la collecte des foies. Ceci a démontré qu’à une semaine de vie, l'activité DNMT et les niveaux de 5'-méthyl-2'-désoxycytidine étaient inférieurs pour les groupes NP et H2O2 par rapport aux témoins. A neuf semaines de vie, l’activité DNMT est restée basse pour le groupe NP alors que les niveaux de 5'-méthyl-2'-désoxycytidine étaient plus faibles pour les groupes NP et H2O2 par rapport aux témoins. Ce travail a démontré que l'administration de NP ou de H2O2, tôt dans la vie, induit une hypométhylation de l'ADN persistante en raison d'une inhibition de l'activité DNMT. Finalement, des souris ayant reçu une diète riche en gras et en sucre (HFHS) ont été utilisées comme modèle in vivo de syndrome métabolique. Les souris ont été nourris soit avec un régime standard chow (témoins), soit avec une diète riche en gras et en sucre (HFHS) ou avec une diète HFHS en combinaison avec du GFT505 (30 mg/kg), un double agoniste de PPARα et de PPARδ, pendant 12 semaines. La diète HFHS était efficace à induire un syndrome métabolique étant donnée l’augmentation du poids corporel, du poids hépatique, des adiposités viscérales et sous-cutanées, de l’insensibilité à l’insuline, des lipides plasmatiques et hépatiques, du stress oxydant et de l’inflammation au niveau du foie. Ces perturbations étaient accompagnées d’une déficience dans l’expression des gènes hépatiques PPARα et PPARγ concomitant avec une hyperméthylation de leurs promoteurs respectifs. L’ajout de GFT505 à la diète HFHS a empêché la plupart des effets cardiométaboliques induits par la diète HFHS via la modulation négative de l’hyperméthylation des promoteurs, résultant en l’augmentation de l’expression des gènes hépatiques PPARα et PPARγ. En conclusion, GFT505 exerce des effets métaboliques positifs en améliorant le syndrome métabolique induit par l'alimentation HFHS via des modifications épigénétiques des gènes PPARs. Ensemble, les travaux de cette thèse ont démontré que le stress oxydant provenant de la nutrition induit d’importants changements épigénétiques pouvant conduire au développement du syndrome métabolique. La nutrition apparait donc comme un facteur crucial dans la prévention de la reprogrammation fœtale et du développement du syndrome métabolique. Puisque les mécanismes suggèrent que le stress oxydant agit principalement sur les métabolites du cycle de la méthionine pour altérer l’épigénétique, une supplémentation en ces molécules ainsi qu’en antioxydants permettrait de restaurer l’équilibre redox et épigénétique.DNA methylation is one of the epigenetic modifications to CpG islands. This covalent epigenetic modification, catalyzed by DNA methyltransferases (DNMTs), consists of localized cytosine methylation in carbon 5’ of the CpG islands resulting in 5-methylcytosine. DNA methylation is clearly implicated in stable gene inactivation and also in the genetic footprint. It is modulated by nutrition, particularly methyl donors and protein restriction. These epigenetic changes persist later in life and lead to the development of numerous pathologies such as metabolic syndrome and type 2 diabetes. In fact, many key genes undergo a modification to their methylation status in the presence of metabolic syndrome components. This shows that DNA methylation is a major process in the etiology of metabolic syndrome. The first work of this Ph.D focused on writing a journal article that examined the central part of the metabolic syndrome and analyze the role of epigenetic changes that may affect the occurrence of oxidative stress and cardiometabolic complications. Furthermore, intestinal cells Caco-2/15, which have the capacity to differentiate and acquire the physiological characteristics of the small intestine, were used and treated with iron-ascorbate to induce oxidative stress. Iron-ascorbate induced a significant increase in inflammation and lipid peroxidation (malondialdehyde) and alterations of the antioxidant defense (GPx and SOD2) accompanied by epigenetic changes. Moreover, pre-incubation of Caco-2/15 cells with 5-Aza-2′-deoxycytidine, a demethylating agent, and/or Trolox antioxidant normalized the activities of SOD2 and GPx, reduced lipid peroxidation and prevented inflammation. This initial work has shown that changes in the redox and inflammation induced by iron-ascorbate may involve epigenetic changes, particularly DNA methylation. To better define the impact of oxidative stress on the nutritional level, Guinea pigs aged three days were divided into three groups : 1) Control: animals enterally fed with regular chow; 2) Total parenteral nutrition (TPN); 3) H2O2: Control+ i.v. infusion with 350 μM H2O2. After four days, for one group, animals were sacrificed for liver sampling. The other group of animals had free access to regular chow and water until the end of study, 8 weeks later and were sacrificed after this period. This work has shown that at one week of age, DNMT activity and 5’-methyl-2’-deoxycytidine levels were lower in TPN and H2O2 groups compared to controls. At nine weeks, DNMT activity remained lower in TPN group whereas 5’-methyl-2’-deoxycytidine levels were lower in TPN and H2O2 groups. This work has demonstrated that administration of TPN or H2O2, early in life in Guinea pigs, induces a sustained hypomethylation of DNA following inhibition of DNMT activity. Finally, mice that have received a high-fat high-sugar diet (HFHS) were used as in vivo model of metabolic syndrome. Mice were fed either a standard chow diet (controls), a high-fat/high-sucrose (HFHS) diet, or the HFHS diet in combination with GFT505 (30 mg/kg), for 12 weeks. The HFHS diet was effective in inducing metabolic syndrome characteristics in view of increases in body weight, visceral adiposity, insulin insensitivity, plasma and hepatic lipids, oxidative stress and inflammation in liver. These derangements were accompanied with deficient in PPARα and PPARγ hepatic gene expressions and hypermethylation of their respective promoters. Addition of GFT505 to the HFHS diet prevented most of the cardiometabolic effects induced by HFHS diet via negative modulation of promoter hypermethylation, resulting in raised PPARα and PPARγ hepatic gene expression. In conclusion, GFT505 exerts positive metabolic effects by improving HFHS diet-induced metabolic syndrome due to epigenetic alterations of PPARs genes. Together, the work of this thesis has shown that oxidative stress from nutrition can regulate epigenetic that lead to the development of metabolic syndrome. Nutrition appears as a critical factor in the prevention of fetal reprogramming and development of the metabolic syndrome. Since the mechanisms suggest that oxidative stress acts on metabolites of methionine cycle to alter the epigenetic, supplementation of these molecules and antioxidants could help to restore the redox balance and the epigenetic

Authenticated Language Through Games that Contribute to the Interest and Language Acquisition of Learners of English Speakers of Other Languages

　In this particular University classroom setting and in the classes being taught, have been placed in the lowest level in regards to English exposure with my class being their first interaction of a new language, taught purely in English. These particular students in this study were first year Economic students and of Japanese ethnicity being taught at a Japanese University. In this case, one of the the major obstacles faced by professors and English language teachers to second language learners is that of low intrinsic motivation, and an of understanding the needs of the learners being taught; from their perspectives (Scrivener, 2011, pp. 89−94).Students of any age learn much the same as early ages in what is known as the “Questioning Cycle” (Paul, 2003, p. 11). The proposed model of using games and objects (including realia) in the classroom to develop language and grammar skills has proven personally successful for the students who have attended my classes. However, when games or realia are introduced to students of University ages, some difficulties may arise within the classroom and may disrupt the lesson plans themselves. One difficulty that has been an issue is that students can possibly become overly motivated; losing focus on the lesson and the content itself. Adversely, another issue is that the students may feel that such games that include realia are “childlike” and may refuse to involve themselves at all. Both of those aforementioned negative outcomes can be allayed by the use of stating clearly that this activity can be taken as either or all of an active participation mark, in-class participation mark, or bonus point, and that when made as a competition the game becomes more involved for the students. Once the grammar is acquired though physical action and the students are ready to use their texts all three learning senses will have been engaged and the students of the second language: Audial, visual, kinesthetic and with the textbook, written reiteration of that which has already been learned. The benefits of using games and realia in class are that the students are given more chances to verbalize the target language; creating a resulting decrease in teacher involvement with students being given more opportunity for creative thought, initiating the natural thought process of native speakers..論文Articl

Influência da adequação postural em cadeira de rodas na função respiratória de pacientes com amiotrofia espinhal tipo II

Este estudo visou determinar a influência da adequação postural em cadeira de rodas na função respiratória de pacientes com amiotrofia espinhal tipo II (AME). Doze pacientes (idades entre 7 e 24 anos) com diagnóstico de AME II, confirmado por achados clínicos e análise genética, participaram do estudo. Os parâmetros respiratórios - volume minuto (VM), volume corrente (VC), capacidade vital forçada (CVF), pressões inspiratória (PImáx) e expiratória (PEmáx) máximas e pico de fluxo expiratório (PFE) - na cadeira de rodas individual, com adaptações, e em uma cadeira de rodas padrão, isto é, sem reclinação ou inclinação. Os resultados mostram valores melhores estatisticamente significativos de todos os parâmetros respiratórios (VM, p=0,002; VC, p=0,003; CVF, p=0,017; PImáx, p=0,002; PEmáx, p=0,006; e PFE, p=0,007) nas medidas tomadas na cadeira adaptada para a postura adequada. Os resultados permitem concluir que a adequação postural em cadeira de rodas influencia positivamente a função respiratória de pacientes com AME tipo II.This study aimed at determining the influence of adequate wheelchair positioning aids on the respiratory function in spinal muscular atrophy (SMA) type II patients. Twelve patients (aged 7 to 24) with SMA diagnosed by clinical findings and confirmed by genetic analysis, who owned wheelchairs with positioning aids, underwent spirometric assessment - as to minute volume (MV), tidal volume (TV), forced vital capacity (FVC), maximum inspiratory (IPmax) and expiratory (EPmax) pressures, and peak expiratory flow (PEF) - both on their own wheelchair and on a standard wheelchair with no recline or tilt. Results show significantly better values in all assessed parameters (MV, p=0.002; TV, p=0.003; FVC, p=0.017; IPmax, p=0.002, EPmax, p=0.006; and PEF, p=0.007) of measures taken at the patient's own chair, with positioning aids. These results allow for concluding that wheelchair positioning aids may positively influence pulmonary function of patients with type II spinal muscular atrophy

Influência da adequação postural em cadeira de rodas na função respiratória de pacientes com distrofia muscular de Duchenne

The purpose of this study was to determine the influence of wheelchair positioning aids on the respiratory function of patients with Duchenne muscular dystrophy (DMD). Twelve non-ambulatory DMD patients, between 10 to 22 years of age, were evaluated. They were assessed in their adapted wheelchairs and in a standard wheelchair without tilt or reclining. The wheelchairs of the participants possessed adaptations in the backrest and the seat, made according to the specifics of each patient. Minute volume (MV), tidal volume (TV), forced vital capacity (FVC), maximum inspiratory (MIP) and expiratory pressures (MEP) and peak expiratory flow (PEF) were measured. For data analysis we used the paired t-test adopting the significance level of 0.05. The positioning aids resulted in statistically significant better values of all respiratory parameters: MV (8,963.3 and 10,762.5 mL/min; p=0.028), TV (319.1 and 433.6 mL; p=0.005), FVC (1,476.3 and 1,850 mL; p=0.005), MIP (-41.2 and -51.2 cmH2O; p=0.022), MEP (29.6 and 36.7 cmH2O; p=0.004) and PEF (162.1 and 185 L/min; p=0.018). These results may suggest that wheelchair positioning aids can positively influence pulmonary function for non-ambulatory DMD patients.O objetivo deste estudo foi avaliar a influência da adequação postural em cadeira de rodas na função respiratória de pacientes com distrofia muscular de Duchenne (DMD). Participaram 12 pacientes com diagnóstico de DMD e que possuíam cadeira de rodas adaptada com idade variando de 10 a 22 anos. Cada indivíduo foi avaliado na própria cadeira de rodas e em uma cadeira de rodas padrão, ou seja, sem reclinação ou tilt. As cadeiras dos participantes possuíam adaptações no encosto e no assento, confeccionados de acordo com as especificidades de cada paciente. A avaliação consistiu em mensurar o volume minuto (VM), volume corrente (VC), capacidade vital forçada (CVF), pressões inspiratória (PImax) e expiratória (PEmax) máximas e pico de fluxo expiratório (PFE). Para análise dos dados, foi utilizado o teste t pareado, adotando-se o nível de significância de 0,05. As adaptações resultaram em melhores valores estatisticamente significativos de todos os parâmetros respiratórios: VM (8.963,3 e 10.762,5 mL/min; p=0,028), VC (319,1 e 433,6 mL; p=0,005), CVF (1.476,3 e 1.850 mL; p=0,005), PImax (-41,2 e -51,2 cmH2O; p=0,022), PEmax (29,6 e 36,7 cmH2O; p=0,004) e PFE (162,1 e 185 L/min; p=0,018). Nossos resultados sugerem que a adequação postural em cadeira de rodas influenciou positivamente a função respiratória de pacientes com DMD

Prospective Analysis of Food Consumption and Nutritional Status and the Impact on the Dietary Inflammatory Index in Women With Breast Cancer During Chemotherapy

Considering the implications of adverse effects of chemotherapy (CT) and the potential impact of diet on patients’ recovery, this study aimed to prospectively evaluate the association between the consumption of food groups, patients’ Dietary Inflammatory Index (DII®) scores, and their nutritional status. Anthropometric and dietary assessments of 55 women with breast cancer (BC) were performed at three time points. T0 is the time point after the first CT cycle, T1 is the time point after the intermediate CT cycle, and T2 is the time point after the last CT cycle. We identified a significant increase in weight, body mass index, and waist circumference during CT. Consumption of poultry and eggs was higher in T1 when compared to T2, while consumption of total fruit and total vegetables was higher at T0 compared to T1 and T2. The diet became more pro-inflammatory over the course of treatment (X2(2) = 61.127), and was related to higher abdominal adiposity. Total fruit (T0: R2 = 0.208, T1: R2 = 0.095, T2: R2 = 0.120) and total vegetable consumption (T0: R2 = 0.284, T1: R2 = 0.365, T2: R2 = 0.580) predicted DII® change at the three-time points. Meanwhile, consumption of total grains was significantly associated only with T1 (R2 = 0.084) and T2 (R2 = 0.118), and consumption of simple sugars was significantly associated only with T0 (R2 = 0.137) and T1 (R2 = 0.126). Changes in food consumption led to an increase in the inflammatory profile of the diet, suggesting the necessity to improve the guidelines during and after CT. These results reinforce the need to promote healthier eating practices in concert with maintaining a healthy nutritional status in women with BC treated with C

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements