O exercício físico modula o sistema renina angiotensina (SRA), que tem um importante papel na fisiologia cardíaca, especialmente na promoção da hipertrofia cardíaca. O SRA pode ser dividido em dois eixos principais: o eixo clássico – representado pelo receptor AT1 (AT1R) ativado pela angiotensina II (ANG II) – e o eixo alternativo – que é ativado pela interação da angiotensina 1- 7 (ANG 1-7) com o receptor MAS (MASR). O balanço entre os eixos do SRA pode determinar um remodelamento cardíaco fisiológico ou patológico. Estudos têm demonstrado que altos volumes de exercício físico podem desencadear possíveis efeitos deletérios ao sistema cardiovascular. Neste contexto, nosso objetivo foi avaliar a hipertrofia cardíaca, o eixo clássico e o eixo alternativo do SRA no miocárdio de camundongos submetidos a variados volumes e intensidades de treinamento em natação. Para tal, camundongos balb/c foram divididos em três grupos: (I) sedentário (SED), (II) treinados 2x ao dia (T2) sem sobrecarga e (III) treinado 3x ao dia com sobrecarga de 2% do peso corporal (T3), totalizando 6 semanas de treinamento efetivo. Ambos os grupos treinados desenvolveram hipertrofia cardíaca, sem diferença nos níveis de fibrose. Bioquimicamente, observamos um aumento nos níveis do receptor MASR somente no grupo T2, enquanto que os níveis de AT1R aumentaram somente no grupo T3. Contudo, não foi observada alteração na concentração dos peptídeos ANGI, ANGII e ANG 1-7 no tecido cardíaco entre os grupos. Além do mais, o grupo T3 demonstrou um aumento na expressão de miosina de cadeia pesada- β em comparação ao grupo SED e redução da expressão da isoforma- @ em relação ao grupo T2. Em conclusão, nossos resultados sugerem que ambos os protocolos de exercício promoveram uma hipertrofia cardíaca semelhante, mas o protocolo com maior volume e intensidade promoveu uma ativação diferencial dos receptores do SRA e reativação de genes fetais. Estudos que avaliem protocolos com maior duração são necessários para esclarecer se estas mudanças representam uma ativação precoce dos mecanismos relatados para o desenvolvimento de um fenótipo com características patológicas. / Exercise promotes physiological cardiac hypertrophy and induces the activation of the renin angiotensin system (RAS), which plays an important role in cardiac physiology, both through the classical axis – represented by the angiotensin II receptor type 1 (AT1) activated by angiotensin II (ANG II) – and the alternative axis – which is activated by the angiotensin 1-7 interaction with the MAS receptor. However, very intense exercise protocols could have deleterious effects on the cardiovascular system. In this context, we aimed to analyze the cardiac hypertrophy phenotype, as well as the classical (ANGII/AT1) and alternative (ANG1-7/MAS) RAS axes, in the myocardium of mice submitted to varying volume and intensity swimming exercises for the development of cardiac hypertrophy. To this end, male balb/c mice were divided into three groups: (I) sedentary (SED), (II) swimming twice a day (T2) without overload, and (III) swimming three times a day with a 2% body weight overload (T3), totaling six weeks of training. Both training groups developed cardiac hypertrophy. Interestingly, we observed an increase in MAS receptor levels only in group T2, while AT1 levels increased only in group T3. However, no change was observed regarding the levels of angiotensin peptides ANG-I, ANG-II, and ANG1-7, in either group. In addition, group T3 displayed a higher expression of myosin heavy chain-β (MHC-β) and lower expression levels of the alpha isoform (MHC-@). Fibrosis was not observed in any of the groups. In conclusion, our results suggest that both exercise protocols promoted a similar cardiac hypertrophy phenotype, but the protocol applying increased volume and intensity resulted in differential activation of RAS receptors and fetal gene reactivation. Studies applying longer duration protocols could elucidate if these changes represent early activation of mechanisms related to hypertrophy development with phenotypic pathological characteristics.

L’hypertrophie bénigne de la prostate (HBP) est une pathologie qui affecte 50% des hommes dès l’âge de 60 ans et qui conduit à des troubles de la miction. L’HBP se caractérise par une hypertrophie exclusive ou composite de plusieurs compartiments tissulaires de la prostate que sont l’épithélium, le stroma et les fibres musculaires qui définissent respectivement les composantes glandulaire, fibreuse et musculaire de cette pathologie. Il a récemment été montré que les souris dépourvues en récepteurs nucléaires LXR (Liver‐X‐receptor) α (souris lxrα‐/‐) développent une hypertrophie de la prostate dont les signes histologiques évoquent une HBP de type fibreuse. Par ailleurs, un des traitements de l’HBP, vise à éteindre la signalisation androgénique en inhibant la conversion de la testostérone en son métabolite actif, la dihydrotestostérone (DHT). Le phénotype d’hypertrophie de la prostate pourrait donc également s’expliquer par une altération de la signalisation androgénique dans les souris lxrα‐/‐. Dans ce contexte, notre projet de recherche a été centré sur l’étude du rôle des LXR dans l’apparition de l’HBP dans sa composante glandulaire et l’analyse des relations moléculaires associant les signalisations dépendantes de LXRα et du récepteur des androgènes (AR) au sein de la prostate. Le phénotype d’HBP observé dans les souris lxrα‐/‐ résulte d’altérations importantes de l’homéostasie de l’épithélium qui miment la composante glandulaire : 1) une activité sécrétoire accrue ; 2) une altération des processus de sécrétion associée à une altération de l’expression des gènes codant des protéines du transport vésiculaire ; 3) une réponse altérée de certains gènes androgéno‐dépendants associée à une hypersensibilité aux androgènes ; 4) des modifications du réseau paracrine reliant le stroma et l’épithélium. Au final, ces travaux définissent LXRα comme un acteur clé de l’homéostasie prostatique et ouvrent des pistes intéressantes pour la compréhension de l’étiologie de l’HBP chez l’homme. Ces résultats montrent qu’il est possible de moduler la réponse androgénique de la prostate en ciblant LXRα. Ainsi, à plus long terme, l’activation pharmacologique de LXRα constitue une piste potentielle dans le traitement de l’HBP. / Benign prostate hyperplasia (BPH) is a very common prostatic disorder that affects 50% of men after 60 years. In BPH, prostate enlargement causes urinary disorders. BPH is characterized by a hypertrophy of several tissue compartments such as the epithelium, stroma and/or muscle fibers. Hence, three main forms of BPH have been described : glandular, fibrous and muscular form. It has been recently shown that LXR (Liver‐X‐receptor) α (lxrα‐/‐) mice develop a prostate enlargement with histological signs of fibrous BPH. Inhibition of testosterone conversion into DHT is one the most effective pharmacological treatment of BPH. Thus, the lxrα‐/‐ prostate phenotype could be in part due to an alteration of androgen signaling. In this context, the aim of this work was to study the role of LXR in glandular BPH development and to understand the relationships between LXRα and the androgen receptor (AR) dependent signaling pathway in prostate. The prostate enlargement observed in lxrα‐/‐ mice results from major alterations in epithelium homeostasis mimicking the glandular alteration of BPH : 1) increase of secretory activity ; 2) alteration of the secretory process associated with altered expression of vesicular transport protein encoding genes ; 3) a disruption in the response of androgen‐dependent genes associated with androgen hypersensitivity ; 4) changes in the paracrine network between stroma and epithelium. Finally, this work defines LXRα as a key player in prostate homeostasis and opens interesting way to the understanding of BPH etiology. These results show that targeting LXRα modulate the prostate androgenic response. Thus, pharmacological activation of LXRα could constitute a new option for the treatment of BPH.

A hipertrofia cardíaca é uma adaptação do coração frente a estímulos de crescimento, sejam eles patológicos e irreversíveis como a sobrecarga de pressão ou de volume, ou fisiológicos e reversíveis como a gravidez e o exercício físico. A hipertrofia derivada de estímulos patológicos é conhecida como mal adaptativa enquanto que a hipertrofia proveniente de estímulos ditos fisiológicos é conhecida como benéfica ou adaptativa. Embora ambas hipertrofias tenham fatores em comum no que diz respeito ao crescimento do cardiomiócito e adaptações moleculares, elas acabam divergindo para desfechos completamente diferentes. A hipertrofia patológica evolui para um quadro de disfunção cardíaca ao passo que a hipertrofia fisiológica não acarreta nenhum dano funcional ao miocárdio. Essa linha tênue entre um fenótipo e outro envolve mecanismos celulares complexos que ainda precisam ser esclarecidos. Dentro deste cenário, os microRNAs aparecem como reguladores de diversos processos celulares, e têm sido associados ao crescimento miocárdico. Portanto, nosso objetivo foi comparar o padrão de expressão de microRNAs entre os modelos de hipertrofia fisiológica, induzido por natação (SWIM), e o modelo de hipertrofia patológica, induzida por bandeamento aórtico transtorácico (TAC). As análises foram realizadas após 28 dias para o modelo de natação, e 35 dias para o modelo de TAC. A comparação foi realizada através da técnica de microarranjo de microRNAs (Affymetrix). Interessantemente, apenas 20 microRNAs apresentaram níveis de expressão distinta entre os dois modelos de hipertrofia. Destes, 12 microRNAs apresentaram aumento de expressão (miR-193a-3p, miR-299a-5p, miR- 127-5p, miR-214-5p, miR-188-5p, miR-326-3p, miR-6395, miR-547-3p, miR-199a-5p, miR-381-3p, miR-223-3p e miR-199b-5p) e 8 estavam com seus níveis diminuídos (miR11 708-5p, miR-30c-1-3p, miR-22-5p, miR-6921-5p, miR-30a-3p, miR-30e-3p, miR-27a-5p and miR-6975-5p) no grupo TAC em relação ao grupo SWIM. Além disso, apenas 3 microRNAs, miR-21a-5p, miR-206-3p e miR-1983, apresentaram aumento de expressão tanto no grupo TAC quanto no grupo SWIM em comparação aos grupos SHAM e Sedentário, respectivamente. Após isso, foi realizada uma busca por possíveis alvos destes microRNAs na base de dados KEGG Pathway que identificou 4 rotas enriquecidas (665 genes) entre os alvos dos microRNAs reduzidos, e 80 rotas (3394 genes) fortemente associadas aos microRNAs que estavam aumentados no grupo TAC comparado ao SWIM. Conclui-se que existem microRNAs específicos para o desenvolvimento da hipertrofia cardíaca fisiológica, bem como patológica conforme os dados obtidos na análise de microarranjo. Além disso, os possíveis alvos destes microRNAs parecem estar envolvidos em rotas bastante envolvidas no crescimento celular, sobrevivência e adaptação cardíaca. / Cardiac hypertrophy is a heart adaptation in response to growth stimuli whether pathological and irreversible such as pressure overload or physiological and reversible as pregnancy and exercise. Hypertrophy because of pathological stimuli is known as mal adaptive while the one that comes from physiological triggers is known as beneficial or adaptive. Although both have similarities about cardiomyocyte growth and molecular adaptations, they diverge to distinct outcomes. The pathological hypertrophy evolves to a pattern of cardiac dysfunction while the physiological one does not cause any damage to the heart. This tenuous line between those phenotypes involves complex cellular mechanisms that need to be clarified. In this context, microRNAs are considered as regulators of many biological processes, and have been associated to myocardial growth. Therefore, our aim was to compare microRNA expression between physiological (swiminduced) and pathological (TAC-induced) hypertrophy. The analysis was performed after 28 days for SWIM protocol and 35 days for TAC model. The comparison was done using microRNA microarray technology (Affymetrix). Interestingly, only 20 microRNAs were differential expressed between both models. Out of those, 12 were up regulated (miR- 193a-3p, miR-299a-5p, miR-127-5p, miR-214-5p, miR-188-5p, miR-326-3p, miR-6395, miR-547-3p, miR-199a-5p, miR-381-3p, miR-223-3p and miR-199b-5p) while 8 were down regulated in TAC group compared to SWIM group. Besides, only 3 microRNAs, miR-21a-5p, miR-206-3p and miR-1983, were upregulated in TAC and SWIM model compared to SHAM and SED groups. After that, a search at KEGG Pathway database retrieved 4 pathways (665 genes) enriched with targets from microRNAs downregulated and 80 pathways (3394 genes) enriched with targets from up-regulated microRNAs in in 13 TAC group compared to SWIM group. In conclusion, there are microRNAs specific committed to the physiological cardiac hypertrophy development as well to the pathological cardiac growth as observed in our microarray data. Furthermore, the possible targets of those microRNAs could be involved in pathways associated with cellular growth, survival and cardiac adaptation.

Orientadora: Profa. Dra. Marcela Sorelli Carneiro Ramos / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Biossistemas, 2017. / As doencas cardiovasculares correspondem ao maior risco de morte subita em todo o mundo, a populacao mundial tem se tornado cada vez mais sedentaria e junto as doencas cardiovasculares outros problemas de saude publica aumentam como a obesidade e diabetes mellitus. Os gastos com a saude publica aumentam muito devido a maior incidencia de doencas associadas ao sedentarismo, obesidade, tabagismo, estresse, hipertensao arterial entre outros. Especificamente a obesidade e considerada uma epidemia mundial, que esta associada aos habitos alimentares e sedentarismo, e esta amplamente relacionada ao fator de risco cardiovascular como hipertensao arterial, resistencia insulinica, dislipidemia e diabetes mellitus, que favorecem o processo aterosclerotico e a ocorrencia de eventos cardiovasculares. Ha uma maior prevalencia de hipertensao arterial em individuos obesos e presenca de hipertrofia cardiaca, que e a maior condicao de morbimortalidade cardiovascular. Trata-se de uma doenca cronica relacionada a eventos pro-inflamatorios com acao de diversas citocinas e quimiocinas alem de hormonios envolvidos na resposta imunologica inata. Os receptores Toll-Like fazem parte da Resposta Imunologica Inata e estao presentes em diversos tecidos, incluindo o coracao. Quando ativados desencadeiam uma resposta intracelular, ativando fatores transcricionais, como NF-kB, que leva a transcricao genica de citocinas inflamatorias: IL-6, TNF-¿¿, INF-gama, IL-1. Algumas doencas cardiovasculares sao antecedidas por inflamacoes sistemicas ou locais, demonstrando que as citocinas sao responsaveis por modular o trofismo cardiaco. Diante do exposto, uma analise mais completa envolvendo obesidade e processos inflamatorios com o risco cardiovascular se faz necessaria para a compreensao de moleculas e vias de sinalizacao, reguladas nessa patologia. O presente estudo tem como objetivo avaliar a contribuicao dos fatores inflamatorios na hipertrofia cardiaca induzida por modelo experimental de obesidade. Para tanto, foram utilizados camundongos C57Bl/6 e camundongos FVB/NJ submetidos ao tratamento com dieta rica em gordura contendo 23% proteina, 35,5% carboidrato e 35,9% gordura e foram comparados aos grupos chow (controle) submetidos a dieta composta por 19% de proteina, 56% de carboidrato, 3,5% de gordura por 68 dias de tratamento. Os animais C57Bl/6 apresentaram maior ganho de peso em relacao aos FVB/NJ ao final dos 68 dias de dieta High Fat. O aumento de colesterol serico, insulina, glicemia, epiWAT (epididymal white adipose tissue) foi maior nos animais C57Bl/6. As duas linhagens apresentaram Heart Weight/Body Lenght e Heart Weight/Tibia Lenght maior em relacao ao grupo Chow, ou seja, grupo controle. Atraves da tecnica de Q-PCR os niveis de mRNA dos marcadores moleculares de hipertrofia cardiaca foram avaliados, e o marcador alfa-actina mostrou-se aumentado na linhagem C57Bl/6 enquanto o marcador ANF (atrial natriuretic factor) mostrou-se aumentado na linhagem FVB/NJ, quando comparados aos seus respectivos grupos chow. Os genes TLR2, TLR4, TNF-¿¿, IL-6, MyD88 e NF-kB tambem foram avaliados. A expressao genica de TLR2, MyD88 e NF-kB mostrou-se diminuida nos animais FVB/NJ submetidos a dieta rica em gordura quando comparados aos animais controle. Na linhagem C57Bl/6, observou-se aumento na expressao genica de TNF-¿¿ e NF-kB. A inducao da obesidade promoveu maior ganho de peso na linhagem C57Bl/6 acompanhado de maior adiposidade abdominal e no tecido epididimal, essa linhagem apresentou maior sensibilidade a insulina e maiores niveis de colesterol na dieta High Fat em relacao a linhagem FVB/JN. Houve remodelamento cardiaco em ambas linhagens e a expressao genica de citocinas inflamatorias foi mais evidente na linhagem C57Bl/6, tambem apresentando maior expressao genica de NF-kB. A linhagem FVB/NJ apresentou diminuicao na expressao de MyD88 e NF-kB na dieta High Fat. Com base nos resultados obtidos verificamos que os camundongos C57Bl/6 mostraram-se mais suscetiveis a dieta enquanto a linhagem FVB/JN mostrou-se mais resistente. / Cardiovascular diseases correspond to an increased risk of worldwide sudden death, the world population has become increasingly sedentary and with cardiovascular diseases other public health problems increase such as obesity and diabetes mellitus. Expenditures on public health increase greatly due to a higher incidence of diseases associated with sedentarism, obesity, smoking, stress, hypertension among others. Obesity specifically is considered a worldwide epidemic, which is associated with eating habits and sedentary lifestyle, and is largely related to cardiovascular risk such as hypertension, insulin resistance, dyslipidemia and diabetes mellitus, which favor the atherosclerotic process and occurrence of cardiovascular events. There is a higher prevalence of hypertension in obese and presence of cardiac hypertrophy, which is a higher cardiovascular morbidity and mortality condition. It is a chronic disease related to pro-inflammatory events with the action of various cytokines and chemokines in addition to hormones involved in the innate immune response. Toll-like receptors are part of the innate immune response and are present in several tissues including the heart. When activated trigger an intracellular response, activating transcriptional factors such as NF-kB, which leads to the genetic transcription of inflammatory cytokines: IL-6, TNF- á, IFN-gamma, IL-1. Some cardiovascular diseases are antecedents of systemic or local inflammations, demonstrating that cytokines are responsible for modulating cardiac trophism. In summary, a more complete analysis involving obesity and inflammatory processes with cardiovascular risk to understand molecules and signaling pathways regulated in this pathology are needed. The present study aims to evaluate the contribution of inflammatory factors in cardiac hypertrophy induced by the experimental model of obesity. For this, C57Bl/6 mice and FVB/NJ mice submitted to a high fat diet containing 23% protein, 35.5% carbohydrate and 35.9% fat were compared to the Chow (control) groups submitted to a chow diet containing 19% protein, 56% carbohydrate, 3.5% fat for 68 days of treatment. The C57Bl/6 animals presented greater weight gain in relation to FVB/NJ at the end of 68 days of high fat diet. Serum cholesterol, insulin, glycemia, epiWAT (epididymal white adipose tissue) increased in C57B1/6 animals. Both strains presented Heart Weight/Body Lenght and Heart Weight/Tibia Lenght higher than the Chow group. mRNA levels of cardiac hypertrophy molecular markers were evaluated through Q-PCR technique, and the alpha-actin marker was shown to be increased in the C57B1/6 lineage while the ANF (atrial natriuretic factor) marker was shown to be increased in the FVB/NJ lineage, when compared to their respective chow groups. TLR2, TLR4, TNF-á, IL-6, MyD88 and NF-kB genes were also evaluated. Gene expression of TLR2, MyD88 and NF-kB were decreased in FVB / NJ animals submitted to a high fat diet when compared to control animals. There was an increase in the gene expression of TNF-á and NF-kB in C57Bl/6 lineage. The induction of obesity promoted greater weight gain in the C57Bl/6 mice followed by a greater abdominal and epididymal adiposity, this lineage presented higher insulin sensitivity and higher cholesterol levels in the High Fat diet when compared to the FVB/JN lineage. There was cardiac remodeling in both lineages and inflammatory cytokines gene expression were more evident in the C57Bl/6 mice, also presenting a greater gene expression of NF-kB. The FVB/NJ mice showed decreased expression of MyD88 and NF-kB on the High Fat diet. Based on the results, we found that the C57Bl/6 mice were more susceptible to the High Fat diet than the FVB/JN strain.

Orientadora: Profa. Dra. Marcela Sorelli Carneiro Ramos / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Biossistemas, 2017. / hipertrofia cardiaca pode ser considerada uma adaptacao fisiologica que se desenvolve quando ha uma sobrecarga cronica imposta ao miocardio. A lesao renal e definida como uma diminuicao abrupta da funcao renal e pode ser considerada uma doenca inflamatoria que pode atingir outros orgaos como, por exemplo, pulmoes, figado e coracao. Evidencias sugerem um papel importante para interleucina-6 (IL-6) nas vias moleculares que iniciam a hipertrofia. O sistema nervoso simpatico (SNS) esta relacionado com a funcao imunologica inervando os orgaos imunes sendo responsavel pela liberacao de catecolaminas. Por sua vez, as catecolaminas quando liberadas no coracao modificam o debito cardiaco por alterarem a forca de contracao nas fibras miocardicas e a frequencia cardiaca. Alem de influenciar funcionalmente a circulacao, o aumento na atividade do SNS, pode exercer um efeito trofico sobre as celulas musculares lisas e miocardicas, podendo assim, contribuir para o trofismo do sistema cardiovascular. O presente estudo buscou avaliar a participacao do Sistema Nervoso Simpatico, no desenvolvimento da hipertrofia cardiaca induzida por lesao renal isquemica. Para tanto, foram utilizados camundongos machos C57BL/6 submetidos a oclusao do pediculo renal esquerdo, por 60 min, seguido de reperfusao por 12 dias, e submetidos ou nao ao tratamento com o ¿À-bloqueador atenolol. Os resultados demostraram que o modelo experimental de isquemia/reperfusao (I/R), foi capaz de gerar um quadro de falencia renal e induzir hipertrofia cardiaca, devido ao processo inflamatorio causado pela lesao. Alem disso, o tratamento com atenolol foi capaz de prevenir o crescimento hipertrofico observado apos a I/R, avaliado pelas relacoes Peso coracao/Peso Corporeo, pelos niveis de RNAm de ANF e BNP (marcadores moleculares de hipertrofia cardiaca) e pelos niveis das citocinas inflamatorias. Da mesma forma, o tratamento reduziu os niveis de expressao genica e proteica do receptor ¿À adrenergico assim como dos demais componentes da via, e tambem a atividade enzimatica de PKA. Os niveis de noradrenalina tambem se mostraram elevados apos isquemia e reperfusao, apresentando uma relacao com a hipertrofia observada, sugerindo um papel importante do SNS na regulacao do quadro hipertrofico. Diante do exposto, os dados apresentados demonstram uma sensibilidade do tecido cardiaco para as acoes do SNS, o qual pode estar presente na regulacao de mecanismos que levam a patogenese da hipertrofia cardiaca neste modelo. / Cardiac hypertrophy is a physiological adaptation that develops when a chronic overload is imposed on the myocardium. Kidney damage is defined as an abrupt decrease in kidney function and can be considered an inflammatory disease that can target other organs such as the lungs, the liver and the heart. Evidence suggests an important role for interleukin-6 (IL-6) in the molecular pathways that initiate hypertrophy. The sympathetic nervous system is related to the immune function by innervating the immune organs and also being responsible for the release of catecholamines. On the other hand, the catecholamines released in the heart modify the cardiac output because they change the contraction force of the myocardial fibers and the heart rate. An increase in the activity of the SNS, which functionality influencescirculation, can exert a trophic effect on the smooth and over myocardial muscle cells, thus contributing to the trophism of the cardiovascular system. The present study aimed to evaluate the participation of the Sympathetic Nervous System in thedevelopment of cardiac hypertrophy induced ischemia/reperfusion animal model. Therefore, C57BL / 6 mice were submitted to left renal pedicle occlusion for 60 min, followed by reperfusion for 12 days, with or without treatment with the â-blocker atenolol. The results demonstrated that the experimental model of ischemia / reperfusion (I / R) was able to generate renal failure and induce cardiac hypertrophy due to the inflammatory process caused by the lesion. In addition, atenolol treatment was able to prevent the hypertrophic development observed after I / R, performed by heart weight/ bodyweight ratios, ANF and BNP mRNA levels (molecular markers of cardiac hypertrophy), and cytokine levels. Similarly, the treatment reduced the levels of gene and protein expression of the â-adrenergic receptor as well as of the other components of the pathway and enzymatic activity of PKA. Noradrenaline levels were also elevated after ischemia / reperfusion, showing a relationship with the hypertrophy phenomenon and therefore suggesting an important role of SNS in the regulation of hypertrophic conditions. In conclusion, this data indicates a sensitivity of the cardiac tissue to the actions of the SNS, which may be present in the regulation of mechanisms that lead to the pathogenesis of cardiac hypertrophy in this model.

La masse musculaire est largement régulée par des voies de signalisation contrôlant l'équilibre entre la synthèse et la dégradation des protéines myofibrillaires. Ainsi, la myostatine, membre de la superfamille des TGFβ, cible un certain nombre de réseaux de signalisation impliqués dans la régulation de la masse musculaire, notamment la voie de signalisation Akt/mTOR. La myostatine est un des inhibiteurs majeurs de la myogenèse en exerçant un contrôle négatif sur la prolifération et différenciation des myoblastes. A l’heure actuelle, la myostatine est au centre de nombreuses stratégies thérapeutiques notamment dans le cadre de thérapies visant à améliorer la fonction musculaire dans les cas d’atrophie ou myopathies. Les protéines GASP-1 et GASP-2, deux protéines sécrétées contenant plusieurs domaines associés à des inhibiteurs de protéases, ont été décrites comme antagonistes de la myostatine. L’Unité de Génétique Moléculaire Animale a mis en place des stratégies in vitro et in vivo afin de déterminer les fonctions des protéines GASP, notamment dans le contexte myogénique. Dans un premier temps, l'équipe a généré une lignée de souris transgéniques TgGasp-1 sur-exprimant le gène Gasp-1. Cette lignée présente une augmentation globale du poids des muscles squelettiques et une hypertrophie, conséquences d'une inhibition de la myostatine. Cependant, contrairement aux souris knock-out pour la myostatine (Mstn-/-), cette lignée ne présente nid’hyperplasie, ni de changement dans la proportion des différents types de fibres musculaires, ni de variation de métabolisme.Afin de mieux comprendre le rôle des protéines GASP dans le développement musculo-squelettique,deux approches complémentaires ont été développées au cours de cette thèse.Une première approche in vivo, avec l'étude d'une lignée murine TgGasp-2 sur-exprimant le gène Gasp-2, a permis de mettre en évidence un phénotype musculaire semblable aux souris sur-exprimant Gasp-1. En effet, l'analyse phénotypique de ce modèle murin montre à 12 semaines, une augmentation globale du poids des souris et de certains muscles squelettiques due à une hypertrophie des fibres musculaires. Comme pour les souris sur-exprimant Gasp-1, à la différence des souris Mstn-/-, le nombre total de fibres des souris TgGasp-2 et leur métabolisme ne présentent pas de variation parrapport aux souris sauvages. Une seconde approche in silico, suite à une étude transcriptomique et protéomique à partir de modèles murins sur-exprimant ou non GASP-1, a permis d'identifier différents processus biologiques et voies de régulation contrôlées par GASP-1. / Muscle mass is largely regulated by signaling pathways controlling the balance between synthesis and degradation of myofibrillar proteins. Thus, myostatin, a member of the TGFβ superfamily, targets a number of signaling networks involved in the regulation of muscle mass, in particular the Akt / mTOR signaling pathway. Myostatin is one of the major inhibitors of myogenesis by exerting a negativecontrol on the proliferation and differentiation of myoblasts. Today, myostatin is involved in many therapeutic strategies which aim to improve muscle function in cases of atrophy or myopathies.GASP-1 and GASP-2 are two secreted proteins containing several domains associated with protease inhibitors, and described as myostatin antagonists. The Animal Molecular Genetics laboratory has developed in vitro and in vivo strategies to determine the functions of GASPs proteins in a myogenic context. First, we generated a transgenic mouse line TgGasp-1 over-expressing the Gasp-1 gene. This line shows an overall increase in skeletal muscle weight and hypertrophy, a consequence of myostatin inhibition. However, unlike myostatin knockout mice (Mstn -/-), this line shows neither hyperplasia, nor change in the proportion of different types of muscle fibers. Moreover, the global metabolism is not affected. In order to better understand the role of GASPs proteins in musculoskeletal development, two complementary approaches were developed during this thesis :(i) the study of a murine TgGasp-2 line over-expressing Gasp-2 reveals a muscular phenotype similar to the TgGasp-1 mice. At 12 weeks, we observed an overall increase in body and some skeletal muscles weight due to a hypertrophy of the myofibers. As the TgGasp-1 mice, and unlike the Mstn -/- mice, the number of fibers and the metabolism of TgGasp-2 mice did not vary compared to the wildtype mice (ii) In silico analyses allow us to identify different biological processes and regulated pathways controlled by GASP-1.

Made available in DSpace on 2014-06-11T19:32:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-07-05Bitstream added on 2014-06-13T20:04:48Z : No. of bitstreams: 1 morales_dc_dr_botfmvz.pdf: 1150740 bytes, checksum: 82142a24852f131d92e839bf0cd1454f (MD5) / O objetivo do presente estudo foi identificar as isoformas da Cadeia Pesada de Miosina (Myosin Heavy Chain - MyHC) por eletroforese (SDS-PAGE), nos músculos Semitendinosus por biopsia durante o crescimento e ao abate e no músculo Longissimus dorsi ao abate. Foram utilizados 20 bovinos inteiros da raça Nelore submetidos ao modelo biológico superprecoce em um delineamento inteiramente casualizado. Foi realizada a caracterização morfológica das fibras musculares quanto ao tipo (SO, FOG e FG) e diâmetro nos mesmos músculos. Em relação ao músculo Semitendinosus somente foram identificadas duas bandas da cadeia pesada de miosina, a MyHC do tipo I e a MyHC do tipo II sem diferenciação da isoforma do tipo II e no músculo Longissimus dorsi foram identificadas as isoformas dos tipos I, II a e II x. Quanto a caracterização dos tipos de fibras no músculo Semitendinosus as mesmas estavam distribuídas em mosaico com predomínio de fibras glicolíticas FOG e FG e houve um aumento significativo (P<0,05) da área dos três tipos de fibras da biopsia para o abate. No músculo Longissimus dorsi constatou-se predominância de fibras do tipo FG em relação as fibras do tipo FOG e SO (P<0,05). Também em relação ao diâmetro das mesmas, as fibras SO apresentaram menor diâmetro (P<0,05) em relação aos demais tipos. Comparando-se os dois músculos no abate, observa-se que o músculo Longissimus dorsi apresenta maior área (P<0,05) tanto em relação as fibras SO como quanto as fibras FG. Com relação ao diâmetro observa-se maiores valores (P<0,05) também para as fibras do músculo Longissimus dorsi, principalmente em relação as fibras FG. / The objective of this study was identify the myosin heavy chain isoforms in Semitendinosus (biopsy and slaughter) and Longissimus dorsi (slaughter) by electrophoresis (SDS PAGE) and the muscles fiber types (SO, FOG and FG) in Brazilian yearly cattle system - Superprecoce. Were used twenty young bulls Bos indicus (Nellore) in completely randomized design. In relation of Semitendinosus muscle were identified only two MyHC isoforms (type I and II) without any diferentiation of type II, and in the Longissimus dorsi muscle were identified the MyHC isoforms I, II a and II x. About the characterization of fiber types, in the Semitendinosus, the same were distributed in Mosaic with predominance of the FG and FOG fibers and siginificant increase (P<0,05) of the fibers of biopsy to slaughter. In Longissimus dorsi muscle were observed predominance of FG fibers in relation to FOG and SO fibers (P<0,05) and in relation to diameter, the SO fibers showed smallest values. Comparing the two muscles, the Longissimus dorsi, showed high area in relation the SO and FG fibers and high diameter especially in the FG fibers.

Inflammation plays a key role during pathological hypertrophy and heart failure. Whilst the roles of pro-inflammatory cytokines are relatively well understood, little is known about the anti-inflammatory cytokines in the heart. Interleukin-10 (IL-10) is a major anti-inflammatory cytokine that is expressed in the heart and may play a crucial role during cardiac remodelling. IL-10 exerts its function by binding to the IL-10 receptor (IL-10R). The primary aim of the PhD study was to investigate the effects of the ubiquitous ablation of IL-10R1 gene during pressure overload induced hypertrophy and to characterise the downstream pathway regulated by IL-10R1 in the heart following pressure overload. The second aim was to investigate the effects of cell specific ablation of IL-10R1 in both the macrophages and cardiomyocytes during pressure overload induced hypertrophy and to identify the specific site where IL-10R1 regulates hypertrophy in the heart. During this study three mouse lines were used: IL-10R1 global knockout (IL-10R1-/-), IL-10R1 macrophage-specific knockout (IL-10R1mKO) and IL-10R1 cardiomyocyte-specific knockout (IL-10R1cKO).Mice with systemic ablation of IL-10 receptor1 (IL-10R1-/-) displayed a significant increase in hypertrophy following two weeks of transverse aortic constriction (TAC) as indicated by heart weight/tibia length ratio (HW/TL). This was accompanied by a significant increase in cardiomyocyte surface area as well as expression of hypertrophic markers such as brain natriuretic peptide (BNP) and Atrial natriuretic peptide (ANP). The IL-10R1-/- mice also had a significant increase in cardiac fibrosis when compared to the WT TAC littermates. Importantly, ejection fraction (EF) and fractional shortening (FS) were significantly reduced in IL-10R1-/- mice compared with WT littermates following TAC. The STAT3 pathway is known as the major downstream signalling pathway regulated by the IL-10R via the activation of the JAK1/STAT3 pathway.  Western blot analysis showed that activation of the STAT3 signalling pathway was significantly reduced in IL-10R1-/- mice following TAC, indicating the possible involvement of this pathway. Furthermore, expression of STAT3 target genes: suppressor of cytokine signalling (SOCS3), tissue inhibitor of metalloproteinases3 (TIMP-3) and heme oxygenase (HO-1) were downregulated in the IL-10R1-/- mice following TAC. Overall the data obtain from the IL-10R1-/- mice indicate that IL-10R1 signalling plays a protective role in reducing pathological hypertrophy in the heart. Interestingly, IL-10R1mKO mice showed no difference in the hypertrophic response following TAC. Analysis of cardiac function and STAT3 activation also showed no difference between IL-10R1mKO and WT controls. This indicated that the protective effects of IL-10R1 mediated signalling during cardiac pressure overload was unlikely due to the effects in residential macrophages. In contrast, IL-10R1cKO mice displayed an elevated hypertrophic response, reduction of cardiac function and less STAT3 activation after TAC. This phenotype resembled those of IL-10R1 global knockout mice. In conclusion, this PhD study has shown that IL-10R1 mediated signalling in the heart is important in controlling pressure-overload hypertrophy. Using cell-specific knockout mice I have shown that IL-10R signalling in cardiomyocytes and not in macrophages is important in this process. These results will open a new insight in targeting IL-10 receptor in the treatment of myocardial hypertrophy in future.

Introdução: Ao ser usado o retalho de omento dissecado por videolaparoscopia no tratamento de deformidades da mama, foi constatado um significativo aumento do seu volume nos primeiros meses após a sua transposição, em todas as pacientes operadas, o que não é visto com essa magnitude em nenhum outro retalho adiposo. Métodos: Para se estudar o motivo desse aumento de volume, foram realizados estudos histológicos de amostras de omento coletadas no primeiro tempo cirúrgico, logo após sua transposição da cavidade abdominal para a região mamária e, no segundo tempo cirúrgico, durante a complementação de tratamento para a simetrização das mamas de oito pacientes. Foram documentadas as modificações nas medidas morfométricas dos adipócitos (perímetro, diâmetro e área), na densidade microvascular mediante o marcador endotelial CD31 e na expressão imunohistoquímica do fator de crescimento do endotélio vascular (VEGF). Resultados: O aumento do tamanho dos adipócitos e da densidade microvascular foi estatisticamente significativo (P≤0,012). O valor do VEGF foi menor na segunda amostra em relação com a primeira, redução esta que não atingiu significância considerável (P<0,093). Conclusão: Estes resultados sinalizam um aumento no volume celular que se mostrou consistente quando foram utilizados três diferentes processos de medida: perímetro, diâmetro e área dos adipócitos. Além disso, o aumento do número de vasos na segunda amostra sugere que tenha ocorrido neoangiogênese estimulada pelo aumento inicial dos valores do VEGF. Portanto o aumento do volume do retalho se deve a neovascularização e hipertrofia do adipócito. / Introduction: When laparoscopically harvested omentum flap was used to treat breast deformities, a significant volume increase, which had never been noticed in any other adipose flap, was observed in all the patients in the first months following its transposition. Methods: Histological studies of omentum samples were performed to study the reason for this increase. Samples were harvested at the first surgical time, right after the transposition of the omentum from the abdominal cavity to the breast region, and at the second surgical time, during treatment complementation for breast symmetrization of eight patients submitted to the transposition of the omentum flap. Modifications in the morphometric measurements of the adipocytes (perimeter, diameter, and area), in the microvascular density by the CD31 endothelial marker and in the imunohistochemic expression of VEGF were documented. Results: the increase in adipocyte size and microvascular density was statistically significant (P≤0.012). The value of VEGF was lower in the second sample, which was not significant (P<0.093). Conclusion: These results suggest an increase in cellular volume that was consistent when three different measurement procedures were used: adipocyte perimeter, diameter, and area. Moreover, the increase in the number of vessels in the second sample suggests neoangiogenesis stimulated by the initial increase in VEGF values obtained in the first sample. The flap increase was probably caused by adipocyte hypertrophy, resulting from the neoangiogenesis.

O objetivo desse estudo foi o de investigar os efeitos do treinamento físico resistido e/ou da suplementação com glutamina sobre as vias de sinalização que regulam a síntese e a degradação de proteínas no músculo esquelético de ratos. Os animais foram divididos nos seguintes grupos: 1) controle (C), 2) treinado (T), 3) suplementado com glutamina (G) e 4) treinado e suplementado com glutamina (TG). Não houve alteração na massa do músculo EDL, mas observou-se aumento significativo na área de secção transversa da fibra (AST). Houve aumento no conteúdo das proteínas Raptor e Deptor e TSC1. O grau de fosforilação da Akt, 4EBP-1, p70SK e S6 foram aumentados nos grupos suplementados com glutamina. A atividade do proteassoma 26S diminuiu no grupo exercitado em relação ao controle. Os resultados deste estudo são sugestivos de que o protocolo de exercício físico utilizado causou hipertrofia por aumento da fosforilação de 4EBP-1. Na suplementação com glutamina, foi observado aumento da fosforilação da 4EBP-1 e de S6 elevando a AST no músculo EDL. / The effect of physical exercise training and/or glutamine supplementation on the signaling pathways that regulate synthesis and degradation of proteins in rat skeletal muscles was investigated. The following groups were examined: 1) control (C); 2) physically trained (T); 3) supplemented with glutamine (G); and 4) physically trained and supplemented with glutamine (GT). EDL muscle mass was not changed but a significant increase in cross-sectional area of the fibers was observed. There was an increase in the protein content of the Raptor and Deptor and TSC1. The levels of phosphorylated S6 and 4EBP-1 were significantly increased in the groups supplemented with glutamine. 26S proteasome activity was decreased in the exercised as compared to the control group. The physical exercise protocol used herein caused hypertrophy via phosphorylation of 4EBP-1. Glutamine supplementation led to an increase of the phosphorylation state of 4EBP-1 and S6 raising the AST of the EDL muscle.