O presente estudo avaliou aspectos relacionados ao contexto inflamatório na hipertrofia cardíaca induzida pelos hormônios tiroideanos (HT) e o possível envolvimento do sistema renina-angiotensina (SRA) nesse processo, utilizando análises in vivo e com enfoque maior na abordagem in vitro. Os resultados mostraram algumas alterações em citocinas circulantes e cardíacas de animais tratados com HT. Além disso, as expressões de S100A8 e MyD88 foram aumentadas no coração de ratos submetidos ao hipertiroidismo e em cardiomiócitos em cultura estimulados com HT. S100A8 e MyD88 mediaram a ativação do fator nuclear NF-κB pelos HT, tendo papel crucial para o crescimento hipertrófico de cardiomiócitos tratados com HT. Por fim, a ação dos HT modulando a expressão de S100A8 e NF-κB foi mediada pelo SRA. Estes dados contribuem com o entendimento das bases moleculares da ação dos HT e da relação deste com o SRA na hipertrofia cardíaca. / The present study evaluated inflammation related aspects in cardiac hypertrophy induced by thyroid hormones (TH) and the possible involvement of the renin-angiotensin system (RAS) in this process, by using in vivo and in vitro analysis. The results showed alterations in circulating and cardiac cytokines from TH treated animals. The expression of S100A8 and MyD88 were increased in the heart of hyperthyroid rats and in cultured cardiomyocytes stimulated with TH. S100A8 and MyD88 mediated the nuclear factor NF-κB activation by TH and these factors presented crucial role to the hypertrophic growth of TH-treated cardiomyocytes. Finally, the action of TH on S100A8 and NF-κB expression was mediated by RAS. These data contribute to the knowledge of molecular basis of TH action and the relationship between TH and RAS in cardiac hypertrophy.

O presente estudo avaliou o papel do receptor AT1 de Angiotensina II no desenvolvimento da hipertrofia dos cardiomiócitos promovida pelo T3, bem como a participação dos mecanismos intracelulares deflagrados pelo receptor AT1 neste modelo de hipertrofia cardíaca. O silenciamento do receptor AT1 com RNA de interferência preveniu totalmente o desenvolvimento da hipertrofia dos cardiomiócitos induzida pelo T3. Os cardiomiócitos tratados com T3 demonstraram uma rápida ativação da via da Akt/GSK-3/mTOR, a qual foi atenuada ou prevenida pelo silenciamento do receptor AT1. Ainda, a expressão de Angiotensina I/II no lisado celular e a expressão do receptor AT1 foram rapidamente aumentados pelo T3. Esses dados demonstram pela primeira vez que o receptor AT1 é um mediador crítico da hipertrofia dos cardiomiócitos induzida pelo T3, bem como para a ativação da via da Akt, sugerindo que a via Ang I/II-AT1-Akt/GSK-3/mTOR corresponde a um potencial mediador dos efeitos tróficos exercidos pelo T3 nessas células. / The present study investigated the role of Angiotensin type 1 receptor (AT1R) in T3-induced cardiomyocyte hypertrophy, as well as the participation of the intracellular mechanisms mediated by AT1R in this cardiac hypertrophy model. The AT1R silencing using small interfering RNA totally prevented the development of T3-induced cardiomyocyte hypertrophy. The cardiomyocytes treated with T3 demonstrated a rapid activation of Akt/GSK-3/mTOR signaling pathway, which was attenuated or prevented by the AT1R silencing. In addition, local Angiotensin I/II (Ang I/II) levels and the AT1R expression were rapidly increased by T3 treatment. These data demonstrate for the first time that the AT1R is a critical mediator to the T3-induced cardiomyocyte hypertrophy, as well as to the activation of the Akt signaling, suggesting that the Ang I/II-AT1R-Akt/GSK-3/mTOR pathway corresponds to a potential mediator of the trophic effect exerted by T3 in cardiomyocytes.

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No. of bitstreams: 2 Dissertação - Cíntia do Carmo e Silva - 2016.pdf: 1705558 bytes, checksum: f3f7616f0bd9d70c3439ec18c38eef3f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-03-21 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Previous studies have demonstrated a protective effect of the Ang-(1-7)/Mas receptor axis on pathological cardiac hypertrophy. Also, the involvement of Mas receptor in the exercise-induced cardiac hypertrophy has been suggested. However, the role of the Ang-(1-7)/Mas receptor on pregnancy-induced cardiac remodeling remains unknown. Thus, the aim of this study was to evaluate the participation of the Mas receptor in the development of pregnancy and hypertrophy, fibrosis and cardiac function during pregnancy. Female Wistar rats were randomly shared in 3 groups: control (W-NP), pregnant (W-P), and pregnant treated with A-779 (W-P + A-779). Wild type and Masknockout mice were distributed in non-pregnant (WT and KO) and pregnant (WT-P and KO-P) groups. Gestational parameters such as, maternal weight, placental weight, fetus weight, fetus/placenta ratio, fertility, Loss pre embryonic, Loss pos embryonic were evaluated. Systolic blood pressure (SBP) was measured by tail-cuff plethysmography. The medial part of the left ventricle (LV) was collected for cardiomyocytes morphometry analysis and extracellular matrix proteins deposition. Echocardiographic analysis was used to evaluate the cardiac function. Mas receptor blockade or genetic deletion of Mas did not alter the fertility or embryonic and fetal development. However, the Mas receptor antagonist decreased placental weight and increased fetus placenta ratio in rats. The pregnant KO mice presented a decreased maternal and fetal weight and increased fetus/placenta ratio. SBP was not changed by pregnancy or A-779 treatment in the Wistar rats. Pharmacological blockade or genetic deletion of Mas receptor attenuates the pregnancy-induced myocyte hypertrophy. The A-779 treatment or genetic deletion of the Mas receptor increased the collagen III deposition in LV from pregnant animals. KO mice presented a lower ejection fraction, fraction shortening, stroke volume and higher end systolic volume compared to WT. Interestingly, the pregnancy restored these parameters. In conclusion, these data show that Mas receptor can alter gestational and maternal parameters, and this is involved in the cardiomyocyte hypertrophy and in the control of the collagen III deposition in pregnancy condition. These alterations are associated with improvement of the cardiac function through Mas-independent mechanism. / Estudos anteriores mostraram que o eixo Ang- (1-7) / receptor Mas possue efeito protetor na hipertrofia cardíaca patológica. Além disso, o envolvimento de receptor Mas na hipertrofia cardíaca induzida por exercício tem sido sugerida. No entanto, o papel da Ang- (1-7) / receptor Mas no remodelamento cardíaco induzido pela gestação permanece desconhecido. Diante disto, o objetivo desse estudo foi avaliar a participação do receptor Mas no desenvolvimento da gestação e na hipertrofia, fibrose e função cardíaca durante a gestação. Ratas Wistar foram randomizadas aleatoriamente em 3 grupos: controle (W-NP), gestante (W-P) e gestante tratada com A-779 (W-P + A-779). Camundongas Wild type e Knockout para o receptor Mas foram randominazadas em grupos não-grávidas (WT e KO) e grávidas (WT-P e KO-P). Parâmetros gestacionais como peso materno, peso placentário, peso fetal, razão feto/placenta, fertilidade, perda pré-embrionária e perda pós-embrionária foram avaliados. A pressão arterial sistólica (PAS) foi medida por pletismografia de cauda. A parte medial do ventrículo esquerdo (VE) foi coletado para análise morfométrica do cardiomiócito e deposição de proteínas na matriz extracelular. Análise por ecocardiografia foi utilizada para avaliar a função cardíaca. O bloqueio ou a deleção genética do Mas não altera a fertilidade, o desenvolvimento embrionário ou fetal. No entanto, o bloqueio do Mas reduziu o peso placentário e aumentou a relação feto/placenta nas ratas. Já nos animais KO gestantes foi observado menor ganho de peso materno e fetal, o que acarretou em aumento da razão feto/placenta. A PAS não foi alterada pela gestação ou tratamento com A-779 nas ratas Wistar. O bloqueio farmacológico ou deleção genética de receptor Mas atenuou a hipertrofia dos miócitos induzida pela gravidez. O tratamento A-779 ou deleção genética do receptor Mas aumentou a deposição de colágeno III do VE das gestantes. KO apresentaram uma menor fração de ejeção, fração de encurtamento, volume sistólico e aumento do volume sistólico final em comparação com WT. Curiosamente, a gravidez restaurou esses parâmetros. Em conclusão, estes dados demonstraram que o receptor Mas pode alterar parâmetros maternos e gestacionais, bem como está envolvido na hipertrofia dos cardiomiócitos e no controle da deposição de colágeno III na gestação. Essas alterações estão associadas com a melhora da função cardíaca por meio de mecanismos independente do Mas

O uso de esteróide anabolizante é cada vez maior por pessoas que praticam exercícios como forma de lazer, sem se importarem com os possíveis efeitos colaterais, o que vem se tornando um importante problema de saúde pública. Dentre os seus principais efeitos colaterais, destacamos a hipertrofia cardíaca, que parece ser ainda mais pronunciada quando associado ao treinamento físico, sendo esta relacionada a maior atividade da enzima conversora de angiotensina cardíaca. Tendo em vista esse cenário, o presente trabalho visa verificar a participação do sistema renina angiotensina aldosterona sobre a hipertrofia cardíaca e síntese de colágeno induzida pelo esteróide anabolizante, associado ao treinamento físico por natação em ratos, por meio do bloqueio de receptores AT1 com Losartan e dos receptores de mineralocorticóides com Espironolactona. Resultados mostram que a administração de esteróide anabolizante aumenta a ativação do sistema renina angiotensina aldosterona cardíaco, o qual está diretamente relacionado aos seus efeitos colaterais, visto que o bloqueio dos receptores AT1 ou dos RM inibiu esses efeitos. Sendo mostrado pela primeira vez, os efeitos do esteróide anabolizante sobre o aumento na expressão do gene da aldosterona sintase e da enzima 11-HSD2, sugerindo os efeitos dos esteróides anabolizantes sobre o aumento da síntese e atividade da aldosterona cardíaca / The anabolic steroid use is growing by recreational exercise practitioners, without worried about the possible collateral effects, becoming an important problem of public health. Among its deleterious effects we detach the cardiac hypertrophy, that looks to be still bigger when the swimming training was associated, being is related to bigger activity of the cardiac angiotensin converter enzime. With that, the present work is going to verify the renin angiotensin aldosteron system participation about the cardiac hypertrophy and collagen synthesis prompted by the anabolic steroid and the association with the swimming training in rat by means of the AT1 receivers blockade with Losartan and of the mineralocorticoids receivers blockade with Espironolacton. Our results show that the anabolic steroid administration increased the cardiac rennin angiotensin aldosteron system activity, that is straightly related to its deleterious effects, seen that the AT1 receivers blockade or the mineracorticoids receivers blockade inhibited those effects. Being shown by the first time the anabolic steroids effects about the increase of the aldosterone sintase gene expression and of the 11-HSD2 enzyme, suggesting the anabolic steroids effects about the cardiac aldosterone synthesis and activity increase

O treinamento físico aeróbio (TF) e a hipertensão arterial (HA) induzem hipertrofia cardíaca (HC) com características diferentes, e entre as diferenças moleculares podem estar a elucidação de abordagens terapêuticas como os microRNAs (miRNAs). Selecionamos de dados de miRNAarray, 15 miRNAs cardíacos induzidos por dois protocolos de treinamento físico de natação (TF) e comparamos com o miRNAarray em modelo de hipertensão arterial (animais espontaneamente hipertensos, SHR). Foram selecionados 4 miRNAs de interesse (miRNA-27a, 27b, 126 e 29c) que seguiram para a confirmação de sua expressão por qRT-PCR. Destes, selecionamos o miRNA-29c para que fosse realizada a modulação in vivo em SHR jovens. Foi realizada injeção cardíaca intramuscular de partículas de vetor lentiviral para a superexpressão do miRNA-29c. Foram testadas duas doses: baixa (B), 0,6x109 pv/animal e alta (A), 3x109 pv/animal; e por dois períodos de tratamento: 7 e 14 dias. Foi avaliada a expressão de GFP em fígado e coração por western blott para observar a eficiência da transdução viral in vivo. Os efeitos do tratamento na pressão arterial (PA) foram analisados por pletismografia de cauda; na HC pela razão VE/PC (peso do ventrículo esquerdo/peso corporal), peso do coração/PC e (cor/PC), e pelo diâmetro de cardiomiócitos (dCMO) por histologia. qRT-PCR foi utilizado para investigar a expressão do miRNA-29c e seus alvos, colágeno do tipo I e do tipo III (COLIAI e COLIIIAI). O conteúdo de colágeno também foi medido por análise histológica (picrossírius), pela fração volumétrica de colágeno (% col), e pela concentração de OHprolina no VE. Os grupos que receberam baixa dose das partículas lentivirais foram positivos para GFP em coração e fígado, tendo sido assumida a dose baixa como eficiente para futuras transduções. Todos os grupos tratados apresentaram aumento da expressão do miRNA-29c. A expressão gênica do COLIAI diminuiu para os grupos tratados o que não ocorreu para o COLIIIAI. A fração volumétrica foi menor em todos os grupos tratados o que mostra evidência que o tratamento foi eficaz para diminuir a concentração de colágeno cardíaco. Houve diminuição no cor/PC de 7-11% para os grupos SHR7A e SHR7B, que foi concatenada com um aumento no dCMO, com diminuição da fibrose. Nossos resultados sugerem, portanto, que o tratamento com o miRNA29c induz remodelamento cardíaco benéfico, abrindo perspectivas para investigações adicionais sobre terapias antifibróticas para doenças cardiovasculares / Both aerobic exercise training (ET) and Hypertension (HY) induce different cardiac hypertrophy (CH) phenotypes which molecular differences and may lead to new targets for therapies in cardiovascular disease, as microRNAs (miRNAs). We selected 15 miRNAS that were changed by ET from miRNAarray data and compared them with other from HY miRNAarray data. Four miRNAs were selected for qRT-PCR confirmation: miRNA-27a, 27b, 126 e 29c. Among then, miRNA 29c was choosen to be modulated by lentiviral vector due its role in fibrosis regulation. Intramuscular cardiac injection of the lentiviral vector particles was performed following two doses; low-dose , 0,6x109 vp/rat and high 3x109 vp/rat; and for two different times (7 and 14 days). The transduction efficiency was assessed by GFP expression by western blot. Blood pressure (BP) was measured by caudal pletysmography, CH was analysed by ratio LVw/BW (left ventricle weight/body weight), heartw/BW (heart weight/body weight) and by cardiomyocyte diameter (dCMO). qRT-PCR was used to assess miRNA-29c expression and its targets COLIAI and COLIIIAI gene expression. The LV collagen content was assessed by histology (Picrossirius red), by collagen volume fraction, and by Hydroxiproline concentration. Both groups that received the lowe doses were GFP positive in the heart and liver tissue,We assumed that low doses were better for future in vivo transduction. BP did not increase to SHR14A and SHR14B, what did not occurred to the 7 days groups. The miRNA-29c expression increased in all treated groups versus their control (CSI). COLIAI expression decreased in treated groups, while COLIIIAI did not change. Collagen volume fraction decreased in all treated groups, which shows that the treatment was efficient to decrease the cardiac collagen. Heart/BW decreased 7-11% in SHR14B and SHR14A and there were an increase in dCMO in all treated groups, that shows that cardiac remodeling of treated SHR included an increase in size of CMO and a decrease in cardiac fibrosis Our data suggests that there is a beneficial cardiac remodeling after treatment with miRNA-29c, which opens perspective for further investigation of antifibrotic therapies for cardiovascular disease

Abstract Heart failure (HF) is a complex pathological state, involving simultaneous alterations in several signalling pathways and changes in gene programming. In HF, activation of the neurohumoral factors and renin-angiotensin-aldosterone (RAA) system occurs as a compensatory mechanism to combat the abnormal ventricular function. Developments in cardiac gene delivery methods have exerted a significant impact to treat HF and to discover the novel molecular mechanisms associated with HF and other cardiac diseases. This study demonstrated that adenovirus–mediated gene delivery of B-type natriuretic peptide (BNP) into the anterior wall of the left ventricle decreased myocardial fibrosis and increased capillary density. Post-infarction BNP improved systolic function associated with normalization of cardiac sarcoplasmic reticulum Ca2+-ATPase (SERCA) 2 expression and phospholamban phosphorylation at Thr17. On the other hand, (Pro)renin receptor ([P]RR) gene delivery resulted deleterious effects on cardiac function and (P)RR activation induced distinct angiotensin II (Ang II)-independent extracellular matrix remodelling and worsening of cardiac function. (P)RR gene delivery resulted in Ang II-independent activation of extracellular-signal regulated (ERK1/2) phosphorylation and increased myocardial fibrosis. In conclusion, the present study indicates that myocardial BNP gene delivery can achieve pleiotropic, context-dependent, favourable effects on cardiac function and that BNP can act locally as a mechanical load–activated regulator of angiogenesis and fibrosis. These results also implicate that (P)RR blockers may display additional cardiac effects in addition to its ability to evoke effective RAA system blockade. Overall, the findings of this study provide a better understanding of the molecular mechanisms involved in the biological actions of BNP and (P)RR, and identify BNP and (P)RR as potential novel drug targets for the treatment of HF. / Tiivistelmä Neuroendokriinisellä aktivaatiolla, jonka seurauksena aiheutuu muun muassa verisuonten supistumista ja laajenemista sekä nesteen kertymistä elimistöön, on tärkeä merkitys sydämen vajaatoiminnan kehittymisessä. Neuroendokriininen aktivaatio kompensoi sydämen vajaatoiminnan seurauksena tapahtuvaa kammioiden poikkeavaa toimintaa. Yksi keskeisimmistä verisuonia supistavista tekijöistä on reniini-angiotensiini-aldosteroni (RAA) -järjestelmä, ja verisuonia laajentaviin tekijöihin kuuluvat muun muassa natriureettiset peptidit, kuten B-tyypin natriureettinen peptidi (BNP) ja A-tyypin natriureettinen peptidi. Geeninsiirtomenetelmillä on ollut merkittäviä vaikutuksia uusien hoitomenetelmien kehittämisessä, sydämen vajaatoiminnan syiden selvittämisessä ja uusien kohdegeenien tunnistamisessa sydämen vajaatoiminnan hoitoon. Väitöskirjan tutkimustulokset osoittivat, että suora adenovirusvälitteinen geeninsiirto rotan sydämen vasemman kammion etuseinään on toimiva menetelmä uusien kohdegeenien löytämiseksi sydämen vajaatoiminnan hoitoon. BNP:n geeninsiirto vähensi merkitsevästi fibroosin muodostumista ja lisäsi verisuonten uudismuodostumista sydämessä. Sydäninfarktin jälkeen BNP paransi sydämen systolista toimintaa, johon liittyi aktiivisen kalsiumpumpun, SERCA2:n ja fosfolambaani-proteiinin fosforylaation normalisoituminen. (Pro)reniini reseptorin ([P]RR) geeninsiirto aiheutti angiotensiini II:sta riippumatonta solunulkoisen matriksin uudelleenmuotoutumista ja sydämen toiminnan huonontumista sekä lisääntynyttä sydämen fibroosia. Väitöskirjatutkimus antaa uutta tietoa solunsisäisistä molekulaarisista mekanismeista sydänsoluissa. BNP geeninsiirto aiheutti sydämen tautitilasta riippuvia suotuisia tapahtumia, ja se toimi paikallisesti muun muassa fibroosia ehkäisevänä tekijänä. (P)RR geeninsiirtotulosten perusteella voidaan olettaa, että (P)RR:n salpaus saattaa olla uusi tehokas hoitokeino sydämen vajaatoiminnan hoitoon.

The endocrine heart synthesises and secretes two polypeptide hormones: the natriuretic peptides (NP) atrial natriuretic factor (ANF) and B-type natriuretic peptide (BNP). The biological actions of these hormones serve both acutely and chronically to reduce systemic blood pressure and hemodynamic load to the heart, thus contributing to the maintenance of cardiorenal homeostasis. Considerable effort has been focused on the elucidation of the mechanistic underlying ANF and BNP gene expression and secretion but much remains to be determined regarding specific molecular events involved in the cardiocyte secretory function. These hormones are produced by the atrial muscle cells (cardiocytes), which display a dual secretory/muscle phenotype. In contrast, ventricular cardiocytes display mainly a muscle phenotype. Comparatively little information is available regarding the genetic background for this important phenotypic difference with particular reference to the endocrine function of the heart. We postulated that comparison of gene expression profiles between atrial and ventricular muscles would help identify transcripts that underlie the phenotypic differences associated with the endocrine function of the heart as well as identify signaling pathways involved in its regulation. The cardiac atrial and ventricular transcriptomes were analyzed using oligonucleotide microarrays under normal or chronically induced aortocaval shunt volume-overload conditions. Transcriptional differences were validated by RT-PCR and transcripts of interest were knocked-down by RNAi. Comparison of gene expression profiles in the rat heart revealed a total of 1415 differentially expressed genes between normal atrial and ventricular tissues. Functional classification and pathway analysis identified numerous transcripts involved in mechanosensing, vesicle trafficking, hormone secretion, and G protein signaling. Volume-overloaded animals exhibited a progressive increase in cardiac mass over the four-week time course, an increase in expression of known hypertrophic genes, as well as the differential expression of 700 genes within the atria. Volume-overload specifically downregulated the accessory protein for heterotrimeric G protein signaling RASD1 in the atria. In vitro, knockdown of RASD1 in the atrial-derived HL-1 cells, significantly increased ANF secretion, demonstrating a previously unknown negative modulator role for RASD1. The data developed in this investigation provides insight into the expression profiles of genes particularly centered on the secretory function of the heart under normal and chronic hemodynamic overload conditions. Genome-wide expression profile analysis identified RASD1 as being differentially expressed between cardiac tissues as well as being modulated by chronic volume overload. RASD1 emerges as a tonic inhibitor of ANF secretion. The novel function identified herein for RASD1 in the atria is of considerable interest given the fact that secretory impairment of the cardiac natriuretic hormones can negatively impact cardiovascular homeostasis.

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