Estudo da participação dos receptores de estrógeno na autofagia em modelo celular de taupatia
Data
2023-07
Autores
Nishino, Michelle Sayuri 
Orientadores
Ureshino, Rodrigo Portes
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Em doenças neurodegenerativas classificadas como tauopatias, há o acúmulo de emaranhados neurofibrilares intracelulares formados principalmente pela proteína tau em seu estado hiperfosforilado. Estudos mostram que a modulação da autofagia é uma das estratégias para o tratamento de demências associadas à formação de agregados proteicos e que a administração de medicamentos para reposição estrogênica pode ter efeito neuroprotetor em processos neurodegenerativos decorrentes do envelhecimento. Assim, o objetivo deste trabalho foi estudar a neuroproteção mediada pela participação dos receptores de estrógeno na modulação da autofagia e sua via de ativação molecular em um modelo celular de tauopatia. Os efeitos dos compostos foram observados em um modelo celular de taupatia, que foi desenvolvido a partir da linhagem celular de neuroblastoma humano SH-SY5Y, que foi transduzida com os genes eGFP-tau e Tet-on. O sistema Tet-On possibilita a superexpressão da tau apenas na presença da doxiciclina. Os efeitos também foram observados em modelo de taupatia tridimensional, no qual as células com superexpressão de tau foram plaqueadas em esferoides scaffold-free, feitos em matriz de agarose.
O screening dos compostos agonistas e antagonistas seletivos dos receptores de estrógeno levou em consideração a viabilidade celular e a capacidade de modular a autofagia. O composto selecionado foi o G15, antagonista do GPER1. Este composto foi avaliado quanto a sua capacidade de reduzir a expressão proteica de tau no modelo de taupatia, demonstrando reduzí-la após 24 horas de tratamento e na concentração de 100 μM. No modelo de neuroesferoides, o composto também se mostrou capaz de reduzir a tau, porém sem apresentar a mesma indução de autofagia. Os resultados encontrados permitem concluir que os compostos estrogênicos representam potenciais indutores de autofagia e que podem ser potenciais agentes neuroprotetores, porém mais experimentos são necessários para afirmar sua efetividade.
In neurodegenerative diseases classified as tauopathies, there is an accumulation of intracellular neurofibrillary tangles formed mainly by the tau protein in its hyperphosphorylated state. Studies show that modulating autophagy is one of the strategies for treating dementia associated with the formation of protein aggregates and that the administration of estrogen replacement medications can have a neuroprotective effect on neurodegenerative processes resulting from aging. Thus, the objective of this work was to study neuroprotection mediated by the participation of estrogen receptors in the modulation of autophagy and its molecular activation pathway in a cellular model of tauopathy. The effects of the compounds were observed in a cellular model of tauopathy, which was developed from the human neuroblastoma cell line SH-SY5Y, which was transduced with the eGFP-tau and Tet-on genes. The Tet-On system allows tau overexpression only in the presence of doxycycline. The effects were also observed in a three-dimensional tauopathy model, in which cells with tau overexpression were plated in scaffold-free spheroids, made in an agarose matrix. The screening of selective estrogen receptor agonist and antagonist compounds took into account cell viability and the ability to modulate autophagy. The compound selected was G15, a GPER1 antagonist. This compound was evaluated for its ability to reduce tau protein expression in the tauopathy model, demonstrating a reduction after 24 hours of treatment and at a concentration of 100 μM. In the neurospheroid model, the compound was also capable of reducing tau, but without presenting the same induction of autophagy. The results found allow us to conclude that estrogenic compounds represent potential inducers of autophagy and that they can be potential neuroprotective agents, but more experiments are needed to confirm their effectiveness.
In neurodegenerative diseases classified as tauopathies, there is an accumulation of intracellular neurofibrillary tangles formed mainly by the tau protein in its hyperphosphorylated state. Studies show that modulating autophagy is one of the strategies for treating dementia associated with the formation of protein aggregates and that the administration of estrogen replacement medications can have a neuroprotective effect on neurodegenerative processes resulting from aging. Thus, the objective of this work was to study neuroprotection mediated by the participation of estrogen receptors in the modulation of autophagy and its molecular activation pathway in a cellular model of tauopathy. The effects of the compounds were observed in a cellular model of tauopathy, which was developed from the human neuroblastoma cell line SH-SY5Y, which was transduced with the eGFP-tau and Tet-on genes. The Tet-On system allows tau overexpression only in the presence of doxycycline. The effects were also observed in a three-dimensional tauopathy model, in which cells with tau overexpression were plated in scaffold-free spheroids, made in an agarose matrix. The screening of selective estrogen receptor agonist and antagonist compounds took into account cell viability and the ability to modulate autophagy. The compound selected was G15, a GPER1 antagonist. This compound was evaluated for its ability to reduce tau protein expression in the tauopathy model, demonstrating a reduction after 24 hours of treatment and at a concentration of 100 μM. In the neurospheroid model, the compound was also capable of reducing tau, but without presenting the same induction of autophagy. The results found allow us to conclude that estrogenic compounds represent potential inducers of autophagy and that they can be potential neuroprotective agents, but more experiments are needed to confirm their effectiveness.