Estudo das vias clássicas e alternativas do sistema renina angiotensina em células mesangiais humanas imortalizadas sob influência da frutose

• Autor(a) principal: Yokota, Rodrigo [UNIFESP]
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=6628523; https://repositorio.unifesp.br/handle/11600/52561
• topic: Enzymes; Renin-angiotensin system; Fructose; Mass Spectrometry; Enzimas; Sistema renina-angiotensina; Frutose; Espectrometria de Massas

Fructose is a sugar that has been widely used by the food industry to sweeten and flavor foods, as well as soft drinks and juices. However, unlike glucose, fructose does not stimulate the secretion of insulin and leptin, but rather hormones linked to appetite stimulation, suggesting that these substances may favor weight gain and the development of obesity. Insulin can influence the energy balance through direct actions in the central nervous system and through its influence and interaction with other hormones, such as angiotensin II (Ang II), adrenaline, leptin, growth hormone. The alteration of the RAS activity has been highlighted, since different studies have shown that the increase of the fructose in the diet promotes the activation of the RAS in rats and mice and an increase in the formation of Ang II in mice that received a diet rich in fructose. It is known that proteolytic enzymes are responsible for the breakdown of peptide bonds between amino acids, catalyze many reactions in the metabolic pathways, being very important in the maintenance and regulation of these pathways. Recent studies have shown that changes in the angiotensin converting enzyme I and 2 (ACE and ACE 2), neutral endopeptidase (NEP), chymase, renin and cathepsin D of the Renin Angiotensin System (RAS). The aim of this study was to evaluate the modulation of the RAS under the effect of fructose on human immortalized mesangial cells (CMHI). In this study CMHI in culture were divided into 3 experimental groups: Control (CT, n = 10), 5mM Fructose (F5mM, n = 10) and 30mM Fructose (F30mM, n = 10). The cells that were stimulated with F5 mM and F30 mM showed a decrease in the ACE activity in the intracellular medium, and an increase the extracellular, demonstrating a secretion of the enzyme to the extracellular medium, what suggest that the formation of Ang II in the extracellular occurs by classical pathway. The increase in Ang I levels in the intracellular compartment may be a result of the activities of renin and cathepsin D. We also detected ACE 2 / NEP activities to the formation of Ang (1-7), counterbalancing the actions of Ang II in this cell in order to protect it from pathophysiological changes caused by exposure to fructose. Regarding Chymase, there were no changes in the intracellular compartment, however, it suggests that the Ang II formation pathway is active by the alternative pathway, due to a higher concentration of this enzyme comparing to ACE in this compartment. The modulation of RAS enzymes under the influence of fructose in CMHI has demonstrated that there is a balance between classical and alternative pathways for the formation of Ang II and Ang (1-7) in the intracellular and extracellular. Fructose modulated the localization of the enzymes of the peptide formation pathways, as well as Ang II and Ang (1-7), that was found in the nucleus and perinuclear suggesting that these enzymes play an important role in the formation of peptides that may have an intracrine action and could act in the nucleus promoting the transcription of new genes. Despite of this profile, it will be necessary to understand the secretion of enzymes and their fructose-induced cellular traffic.