Submitted by FERNANDA DA SILVA VON PORSTER (fdsvporster@univates.br) on 2016-07-28T17:39:59Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) 2016JanainadaSilveira.pdf: 1080873 bytes, checksum: 15257c6712478a254c9f0043916a2734 (MD5) / Approved for entry into archive by Ana Paula Lisboa Monteiro (monteiro@univates.br) on 2016-08-30T11:56:09Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) 2016JanainadaSilveira.pdf: 1080873 bytes, checksum: 15257c6712478a254c9f0043916a2734 (MD5) / Made available in DSpace on 2016-08-30T11:56:09Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) 2016JanainadaSilveira.pdf: 1080873 bytes, checksum: 15257c6712478a254c9f0043916a2734 (MD5) Previous issue date: 2016-07 / CAPES / A obesidade é considerada um problema de saúde pública, sendo associada a diversas doenças crônicas. As causas são multifatoriais, envolvendo interações entre numerosos fatores genéticos e ambientais. O receptor β-2 adrenérgico (ADRB2) desempenha um papel importante na regulação da homeostase da energia, atuando no controle da quebra de glicogênio e na mobilização de lipídeos, por meio da ativação da lipólise. O gene codificador desse receptor, o ADRB2, possui muitas variantes genéticas, sendo o polimorfismo rs1042714 um dos mais investigados em fenótipos relacionados com a obesidade, em diferentes populações. Objetivo: O objetivo principal do presente estudo foi verificar se existe interação entre o polimorfismo rs1042714 do gene ADRB2 com o consumo alimentar, e se esta influencia os parâmetros antropométricos e bioquímicos de uma amostra de indivíduos adultos. Metodologia: Foram avaliados parâmetros antropométricos e de consumo alimentar de macro e micronutrientes de 541 indivíduos adultos, de ambos os sexos, frequentados do ambulatório de nutrição do Universidade do Vale do Taquari UNIVATES. Foram também coletadas amostras de sangue periférico de todos os participantes, para análises de parâmetros bioquímicos e extração de DNA, para posterior genotipagem do polimorfismo investigado. Todos os indivíduos incluídos no estudo assinaram um termo de consentimento livre e esclarecido. Resultados: Os resultados dos testes de interação entre o polimorfismo rs1042714 o consumo de micronutrientes indicaram que, em indivíduos portadores do genótipo GG, o aumento do consumo de calciferol está associado com uma diminuição nos níveis de colesterol LDL e na medida da circunferência de cintura. Da mesma forma, nesses indivíduos, o aumento do consumo de sódio está associado com uma diminuição do colesterol LDL. Esses efeitos não foram observados para os indivíduos portadores do alelo C (CC+CG). Conclusão: Nossos achados indicam um possível efeito benéfico do consumo de calciferol e cálcio nos níveis de colesterol LDL e do consumo de calciferol na circunferência da cintura, em indivíduos eutróficos portadores do genótipo GG do polimorfismo rs10422714 do gene ADR2B. Esses resultados, no entanto, são preliminares e estudos que avaliem os mecanismos fisiológicos envolvidos são necessários para conclusões mais robustas. / Obesity is a public health problem and it is associated with several chronic diseases. The causes are multifactorial, involving interactions between several genetic and environmental factors. The β-2 adrenergic receptor (ADRB2) plays an important role in energy homeostasis regulation, acting on the control of glycogen breakdown and mobilization of lipids, through the activation of lipolysis. The gene encoding this receptor, the ADRB2, has many genetic variants, being the polymorphism rs1042714 one of the most investigated in obesity-related phenotypes, in different populations. Objective: The main objective of this study was to investigate if there is an interaction between the rs1042714 polymorphism of the gene ADRB2 with dietary intake, and if this interaction influences the anthropometric and biochemical parameters of a sample of adults. Methodology: Anthropometric parameters and macro and micronutrients food intake were evaluated in a sample of 541 adults, of both sexes, attended on the nutrition outpatient at the University Center UNIVATES. Blood samples from all participants were also collected, for biochemical analysis and DNA extraction, for subsequent genotyping. All subjects included in the study signed an informed consent form. Results: The results of the interaction tests between the polymorphism rs1042714 and the intake of micronutrients indicated that, in patients with the GG genotype, the increase in calciferol intake is associated with a decrease in LDL cholesterol levels and the measured waist circumference. Similarly, in those individuals, the increase in sodium intake is associated with a decrease in LDL cholesterol. These effects were not observed for individuals carrying the C allele (CC + CG). Conclusion: Our findings indicate a possible beneficial effect of the intake of calciferol and sodium in LDL cholesterol levels and waist circumference, in normal weight individuals carrying the GG genotype of rs10422714 polymorphism of the ADR2B gene. These results, however, are preliminary and studies evaluating the physiological mechanisms involved in this process are required for more robust conclusions.

No description available.

L’hypertension constitue un facteur majeur de risque de maladies cardiovasculaires et touche à un pourcentage important de la population humaine. Il s’agit d’une maladie complexe étant donné son caractère multifactoriel. La régulation de la pression artérielle (PA) est sous contrôle de plusieurs gènes, appelés loci pour traits quantitatifs ou QTL, et elle est le résultat de leur interaction. Étant donné que la PA est un trait quantitatif sous contrôle de plusieurs composantes comme les facteurs génétiques et environnementaux, l’étude de l’hypertension est limitée chez les populations humaines. Ainsi la stratégie principale pour l’étude de cette maladie est l’identification de QTL à PA chez des souches congéniques de rat construites à partir des lignées hyper- et normotendues; à savoir les souches Dahl salt-sensitive [1] et Lewis, respectivement. Des études précédentes dans notre laboratoire ont localisé trois QTL à PA au niveau du chromosome 18 chez le rat. Au cours de ce projet, de nouvelles sous-souches ont été construites afin de raffiner la cartographie de ces QTL. Ainsi, les C18QTL1, C18QTL3 et C18QTL4 ont été définis. Des analyses moléculaires ont été effectuées sur deux gènes candidats pour le C18QTL3; à savoir, Adrb2 et Nedd4l associés précédemment à l’hypertension. La comparaison des résultats de séquençage des régions régulatrices et codantes de ces deux gènes, ainsi que leur analyse d’expression par qRT-PCR chez les souches contrastantes DSS et Lewis, n’ont pas montré de différence significative pouvant expliquer la variation du phénotype observé. Des études plus poussées devront être effectuées sur ces deux gènes et, le cas échéant, l’analyse d’autres gènes contenus dans le C18QTL3 devra être entamée afin d’identifier le gène responsable de ce QTL. / Hypertension is a major risk factor in cardiovascular disease and affects a large percentage of human population. It is a complex disease because of its multifactorial nature. Blood pressure (BP) regulation is controlled by several genes, known as quantitative trait loci or QTL, and results from their interaction. Given that BP is a quantitative trait influenced by several components such as genetic and environmental factors, the study of hypertension is limited in humans. As a result, the main strategy in the study of this disease is the identification of BP QTL in congenic rat strains established from hyper- and normotensive breeds, namely, Dahl salt-sensitive [1] and Lewis. Previous studies showed the existence of three QTL in rat chromosome 18. For this project, new congenic sub-strains were developed in order to refine these QTL containing regions. Thus, C18QTL1, C18QTL3 and C18QTL4 were defined. Molecular analyses were carried out for two candidate genes contained in C18QTL3; namely Adrb2 and Nedd4l previously associated with hypertension. Comparison of the sequencing results from regulatory and coding regions of the two genes, as well as their expression analyses, showed no significant difference able to account for the variation of the observed phenotype distinguishing DSS from Lewis. Further investigation of these two genes must be conducted and, if needed, analyses of other genes contained in C18QTL3 should be undertaken in order to uncover the locus responsible for the QTL.

No description available.

Obesity-associated metabolic disorders are amongst the most prevalent causes of death worldwide. Understanding how obesity leads to the development of the Metabolic Syndrome (MetS) and cardiovascular disease (CVD) will enable the development of novel therapies that dissociate obesity from its cardiometabolic complications. Our laboratory views the functional capacity of white adipose tissue (WAT), the organ designed for safe lipid storage, as a key factor in the development of MetS and CVD. At a genetically-defined stage of the aberrant WAT expansion that occurs during obesity, adipocytes undergo a functional failure, resulting in an impaired control of serum free fatty acid (FFA) concentration. In such setting, FFAs and their metabolic derivatives accumulate in other organs, where they cause lipotoxicity, leading to the development of insulin resistance and CVD. We therefore aim to understand the pathophysiological mechanisms that induce adipocyte dysfunction. The past two decades of research have established the immune system as an important regulator of WAT function. The number of adipose tissue macrophages (ATMs), the most abundant immune cell type in WAT, increases during obesity, resulting in WAT inflammation. Multiple genetic and pharmacological intervention studies of murine models of obesity have assigned a causal link between ATM pro-inflammatory activation and WAT dysfunction. However, while the propagation of inflammation in ATMs during obesity has been extensively studied, factors triggering ATM inflammatory activation are less clear. Recently, our lab has observed lipid accumulation in the ATMs isolated from obese mice. Lipid-laden ATMs were pro-inflammatory, leading us to hypothesise that aberrant lipid build-up in macrophages triggers WAT inflammation during obesity. This thesis expands on the initial findings from our lab and describes two novel mechanisms that potentially contribute to lipid-induced inflammatory activation of ATMs. In chapter 3, the role of de novo phosphatidylcholine (PC) synthesis pathway during lipotoxicity in macrophages is addressed. The first part of the chapter demonstrates that lipotoxic environment increased de novo PC synthesis rate in bone marrow-derived macrophages (BMDMs) and ATMs, and that loss of rate-limiting enzyme in de novo PC synthesis pathway, CTP:phosphocholine cytidylyltransferase a (CCTa) diminished saturated FFA-induced inflammation in BMDMs. In the second part, I show that macrophage-specific CCTa deletion did not impact on the development of WAT inflammation or systemic insulin resistance, but had a minor benefitial effect on hepatic gene transcription during obesity. Chapter 4 develops on recent observations of interactions between sympathetic nerves and macrophages in WAT. In the first part of the chapter, I demonstrate that stimulating B2-adrenergic receptor (B2AR), the main receptor for sympathetic neurotransmitter norepinephrine in macrophages, enhanced intracellular triglyceride storage by up-regulating diacylglycerol O-acyltransferase 1 (Dgat1) gene expression in BMDMs. The second part of the chapter shows that macrophage-specific B2AR deletion did not modulate systemic glucose and lipid metabolism during obesity, but mice lacking B2ARs in macrophages demonstrated augmented hepatic glucose production on a chow diet. Furthermore, systemic B2AR blockade or macrophage-specific B2AR deletion in mice did not affect the thermogenic response to cold exposure. Chapter 5 includes the characterisation of B2AR stimulation-induced changes to the global cellular proteome of BMDMs, and a subsequent validation of the role of candidate transcription factors in regulating B2AR agonism-induced gene expression in BMDMs.