| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 3.88 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
A obesidade é um grave problema de saúde pública que afeta quase metade da população mundial e está associada a consequências adversas como a diabetes. A diabetes caracteriza-se por uma capacidade reduzida de controlar o nível de glucose na corrente sanguínea. Um estudo anterior revelou uma nova mutação no gene TMEM67 em indivíduos obesos. Este gene codifica uma proteína que está presente nos cílios, organelos que desempenham um papel no controlo do equilíbrio energético e da homeostase da glucose. Com este trabalho, pretendeu-se recriar a variante TMEM67 c.158A>G numa linha celular hTERT-RPE-1 para perceber como esta variante pode afetar a montagem e função dos cílios, e o seu papel no desenvolvimento da obesidade. Foi também um objetivo estudar o papel do aumento dos níveis de glucose na montagem dos cílios primários, bem como o papel dos cílios primários na resposta celular ao stress oxidativo induzido pela glucose. Foi possível demonstrar que as células hTERT-RPE-1 quando suplementadas com concentrações de glucose mais elevadas não apresentaram diferenças no número de células ciliadas, no entanto, apresentam uma diminuição no comprimento desses mesmos cílios. Observou-se também que as células, nessas mesmas condições, tinham níveis nucleares mais baixos de TXNRD1, um dos principais intervenientes na resposta ao stress oxidativo. Quando estas células foram induzidas a montar cílios, os níveis nucleares do TXNRD1 tendem a aumentar em resposta a níveis mais elevados de glucose. Juntos, estes resultados mostram que a presença de cílios primários afeta drasticamente a resposta celular às concentrações de glucose que são suscetíveis de induzir stress oxidativo.
ABSTRACT - Obesity is a serious public health problem that affects almost half of the world's population and is associated with adverse consequences such as diabetes. Diabetes is characterized by a reduced ability to control the level of glucose in the bloodstream. A previous study revealed a new mutation in the TMEM67 gene in obese individuals. TMEM67 encodes a protein that is present in cilia, organelles that have been shown to have a role in controlling energy balance and glucose homeostasis. With this work, it was intended to recreate the variant TMEM67 c.158A>G in an hTERT-RPE-1 cell line to understand how this variant can affect the assembly and function of cilia, and its role in the development of obesity. It was also an objective to study the role of increased glucose levels in the assembly of primary cilia, as well as the role of primary cilia on the cellular response to glucose-induced oxidative stress. We showed that hTERT-RPE-1 cells when supplemented with higher concentrations of glucose showed no differences in the number of ciliated cells, however, show a decrease in the length of the cilia. It was also observed that cells in these same conditions presented lower nuclear levels of TXNRD1, a major player in oxidative stress response. When these cells were induced to assemble cilia, the TXNRD1 nuclear levels tended to increase in response to higher levels of glucose. Together, these results show that the presence of primary cilia dramatically affects the cellular response to glucose concentrations that most probably induce oxidative stress.
ABSTRACT - Obesity is a serious public health problem that affects almost half of the world's population and is associated with adverse consequences such as diabetes. Diabetes is characterized by a reduced ability to control the level of glucose in the bloodstream. A previous study revealed a new mutation in the TMEM67 gene in obese individuals. TMEM67 encodes a protein that is present in cilia, organelles that have been shown to have a role in controlling energy balance and glucose homeostasis. With this work, it was intended to recreate the variant TMEM67 c.158A>G in an hTERT-RPE-1 cell line to understand how this variant can affect the assembly and function of cilia, and its role in the development of obesity. It was also an objective to study the role of increased glucose levels in the assembly of primary cilia, as well as the role of primary cilia on the cellular response to glucose-induced oxidative stress. We showed that hTERT-RPE-1 cells when supplemented with higher concentrations of glucose showed no differences in the number of ciliated cells, however, show a decrease in the length of the cilia. It was also observed that cells in these same conditions presented lower nuclear levels of TXNRD1, a major player in oxidative stress response. When these cells were induced to assemble cilia, the TXNRD1 nuclear levels tended to increase in response to higher levels of glucose. Together, these results show that the presence of primary cilia dramatically affects the cellular response to glucose concentrations that most probably induce oxidative stress.
Description
Mestrado em Tecnologias Moleculares em Saúde
Keywords
Obesity Diabetes Cilia TMEM67 Oxidative stress Obesidade Cílios Stress oxidativo
Citation
Paiva MF. Mutations in the TMEM67 gene in obese individuals and their role in cilia assembly and function [dissertation]. Lisboa: Escola Superior de Tecnologia da Saúde de Lisboa/Instituto Politécnico de Lisboa; 2022.
Publisher
Instituto Politécnico de Lisboa, Escola Superior de Tecnologia da Saúde de Lisboa